Kantronics KPC-3 Plus ""KPC-3P / KPC-3+"" (Kantronics Packet Communicator 3 Plus) User manual Rev.H

1

Kantronics

KPC–3 Plus

Users Guide: Introduction,

Getting Started,
Modes of Operation,
Command Reference, and
Hardware Specifications

2

Contact Us:

Kantronics

14830 W. 117th St.
Olathe, Kansas 66062

Orders / Inquiries [phone]

FAX [phone]
E-mail [e-mail]
Website: www.kantronics.com

Service / Technical Support [phone] (8 AM to 12PM and 1 to 5 PM Central Time, M-F)

FAX [phone]
E-mail [e-mail]

3

REVISIONS

Revision

Date

Description

A

2003-11-11

Inserted warranty form and revisions page. Deleted reference to
previously supplied molded audio plug with shielded cable.

B

2005-04-28

Added UIDUPE command definition and reference in a number
of locations to the GPS port. Updated “Expanding the RAM”.

C

2005-09-21

Deleted further references to previously supplied molded audio
plug with shielded cable. Deleted reference to Warranty
Registration card. Changed time to file Warranty Registration
from 10 to 60 days. Added e-mailing of Warranty Registration
information. Other cleanup.

D

2005-09-26

Deleted reference to Kantronics HSP cable.

E

2006-05-10

Changed Kantronics address to 3115 W. 6th St., Ste. A.

F

2006-08-22

Removed CE mark pending RoHS Compliance.

G

2011-07-31

Updated contact information, minor text revisions.

H

2015-05-28

Updated to a searchable format.

The KPC-3 Plus is a Kantronics hardware and software design incorporating the AX.25 Level 2 Version 2
Packet protocol as adopted by the American Radio Relay League.

We have attempted to make this manual technically and typographically correct as of the date of the current
printing. Production changes to the TNC may add errata or addendum sheets. Your comments and/or
suggested corrections can be sent to us (see our contact information).

This document was compiled in the U.S.A.

The KPC-3 Plus is manufactured in the U.S.A.

© Copyright 2007-2015 by Kantronics. All Rights Reserved.
Contents of this publication or the firmware within the KPC-3 Plus may not be reproduced in any form without

the written permission of the copyright owner.
KPC-3 Plus is a registered trademark of Kantronics Co., Inc.

KPC-9612 Plus is a registered trademark of Kantronics Co., Inc.
KAM XL is a registered trademark of Kantronics Co., Inc.
NET/ROM is a registered trademark of SOFTWARE 2000.
APRS is a registered trademark of Bob Bruninga, WB4APR.
HyperTerminal is a registered trademark of Microsoft.

4

Warranty Registration

Please take the time to (print this page) fill out the warranty registration form and mail it to Kantronics,
including a copy of your sales receipt, to register your purchase. Refer to the warranty policy in this manual for
further information.

Mail form and sales receipt to:

Kantronics
14830 W 117th Street
Olathe, KS 66062

Warranty Registration

Last Name: First Name:
Call Sign: .
Mailing Address:
City:
State: Zip/Postal Code: Country:
Telephone: E-Mail:
Product: KPC-3+ Serial #:
Date of Purchase: Dealer:

5

IMPORTANT

READ THIS PAGE BEFORE YOU INSTALL YOUR NEW KANTRONICS PRODUCT

This product contains SOFTWARE on Programmable Read Only Memory (PROM) and/or diskette
and/or CD, which is protected by both United States copyright law and international treaty provisions.

If you install or use this product, you will be deemed to be bound by the terms of the SOFTWARE
license shown below. If you do not wish to be bound by such license, return such product and all
associated documentation unused to your supplier for refund of the amount you paid.

License Agreement

1. License. In consideration of payment of the License Fee, which is included in the price of the
product, the Licensee (you) is granted by the Licensor (Kantronics Company, Inc. - Kantronics) a
non-exclusive right to use the SOFTWARE and associated documentation. No ownership rights to
the SOFTWARE or its Documentation are transferred from Kantronics to you.

2. Term. This License Agreement is effective until terminated. You may terminate this Agreement by
destroying the PROM or diskette or CD and documentation. You may not rent or lease the
SOFTWARE, but you may transfer the SOFTWARE and accompanying written materials on a
permanent basis provided you retain no copies and the recipient agrees to the terms of this
Agreement. Kantronics may terminate this Agreement without notice if you violate any terms or
conditions of the Agreement. In the event of termination of the Agreement, provisions relating to

Kantronics’ disclaimers of warranties, limitation of liability, remedies, or damages and Kantronics’

proprietary rights shall survive.

3. Object Code. The SOFTWARE is delivered in object code only. You shall not reverse compile or
otherwise reverse engineer the SOFTWARE.

4. Limited Warranty. This product is covered by the standard Kantronics Limited Warranty, which is
enclosed.

5. General. This License Agreement constitutes the complete Agreement between you and
Kantronics.

The SOFTWARE and/or Documentation may not be exported or re-exported in violation of any export
laws or regulations of the United States of America or any other applicable jurisdiction.

This Agreement shall be governed by and interpreted under the laws of the State of Kansas, United
States of America.

Use, duplication, or disclosure by the Government of the United States is subject to restrictions as set
forth in subparagraph (c)(1)(ii) of the Rights in Technical Data and Computer SOFTWARE clause of
DFARS 252.227-7013.

Kantronics may in its sole discretion, provide you with upgrades of the SOFTWARE and/or
Documentation if you have provided Kantronics your completed Warranty registration with a copy of
your receipt showing the amount you paid.

6

LICENSEE ACKNOWLEDGES HAVING READ AND UNDERSTOOD THIS AGREEMENT AND
AGREES TO BE BOUND BY ITS TERMS. LICENSEE FURTHER AGREES THAT THIS
AGREEMENT IS THE COMPLETE AND EXCLUSIVE STATEMENT OF THE AGREEMENT
BETWEEN LICENSEE AND LICENSOR AND SUPERSEDES ANY PROPOSAL OR PRIOR
AGREEMENT, ORAL OR WRITTEN, AND ANY OTHER COMMUNICATIONS RELATING TO THE
SUBJECT MATTER OF THIS AGREEMENT.

Any questions concerning this Agreement or any other matter relating to Kantronics, Kantronics
products, or business practices, may be sent to us by any of the means on our contact information
page.

7

TABLE OF CONTENTS

Contact Us: ............................................................................................................................................................................................... 2

REVISIONS ............................................................................................................................................................................................. 3

Warranty Registration ............................................................................................................................................................................ 4

License Agreement ................................................................................................................................................................................... 5

LIMITED WARRANTY ......................................................................................................................................................................... 9

Return/Repair Procedures .................................................................................................................................................................... 12

Radio Frequency Interference Statement ............................................................................................................................................. 14

RFI Suppression ................................................................................................................................................................................... 15

FCC Declaration of Conformity: ......................................................................................................................................................... 16

Introduction ............................................................................................................................................................................................ 17

Welcome .............................................................................................................................................................................................. 17

Overview of This “User’s Guide” Manual ........................................................................................................................................... 17

Major Uses of Your KPC-3 Plus .......................................................................................................................................................... 17

Package Contents ................................................................................................................................................................................. 18

Additional Parts for Your Packet Radio Station .................................................................................................................................. 18

Our Assumptions about You ................................................................................................................................................................ 19

Documentation Conventions ................................................................................................................................................................ 19

Overview of Packet Radio ................................................................................................................................................................... 19

.Inside a TNC – the KPC-3 Plus .......................................................................................................................................................... 26

Inside a TNC – the KPC-3 Plus ........................................................................................................................................................... 27

Installing Your KPC-3 Plus .................................................................................................................................................................. 29

The Major Components of Your Station .............................................................................................................................................. 30

Back Panel ........................................................................................................................................................................................... 30

How the Parts of Your Station are Connected ..................................................................................................................................... 33

Connect Your KPC-3 Plus to a Power Source ..................................................................................................................................... 34

Connect your KPC-3 Plus to Your Computer ................................................................ ................................ ...................................... 36

Configure Your KPC-3 Plus ................................................................................................................................................................ 39

Connect the KPC-3 Plus to a Transceiver ............................................................................................................................................ 43

Connecting to a GPS Device (Optional) .............................................................................................................................................. 53

Getting Started ....................................................................................................................................................................................... 54

The Front Panel of the KPC-3 Plus ...................................................................................................................................................... 55

Beginning a Packet Session ................................................................................................................................................................. 55

Giving Commands and Transmitting Data .......................................................................................................................................... 56

NEWUSER Commands ....................................................................................................................................................................... 57

Using NEWUSER Commands ............................................................................................................................................................. 59

Connect to Your Mailbox .................................................................................................................................................................... 60

Monitor Communications From Nearby Stations ................................................................................................................................ 61

Communicate Directly with a Nearby Station ................................................................ ................................ ..................................... 62

Modes of Operation ............................................................................................................................................................................... 64

Packet Mode of Operation ................................................................................................................................................................... 64

Remote Access to Your TNC ............................................................................................................................................................... 74

PBBS (Personal Mailbox) ...................................................................................................................................................................... 76

GPS NMEA Interfacing ........................................................................................................................................................................ 91

GPS Operations .................................................................................................................................................................................... 95

KA-Node ............................................................................................................................................................................................... 104

Introduction to Basic Packet Networking .......................................................................................................................................... 112

K-Net Network node ................................ ................................................................................................................................ ............ 114

K-Net Node Commands ..................................................................................................................................................................... 115

WEFAX Mode ................................................................................................................................................................................... 137

Other Modes of Operation ................................................................................................................................................................. 139

Modem Mode ..................................................................................................................................................................................... 140

Kantronics Host Mode Operation ...................................................................................................................................................... 141

KISS Mode ........................................................................................................................................................................................ 142

Command Reference .......................................................................................................................................................................... 146

Introduction ........................................................................................................................................................................................ 146

Commands ............................................................................................................................................................................................ 151

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Appendix A: Advanced Installation ................................................................................................................................................... 209

Precautions ......................................................................................................................................................................................... 209

Cable Wiring ...................................................................................................................................................................................... 209

Connecting to the Computer (DSUB-25) ........................................................................................................................................... 209

Connecting to your Radios ................................................................................................................................................................. 212

Appendix B: Advanced Information .................................................................................................................................................. 215

Assembly and Disassembly ............................................................................................................................................................... 215

Hard Reset.......................................................................................................................................................................................... 215

Calibration/Equalization .................................................................................................................................................................... 216

PTT (Push-to-Talk) Watchdog Timer ................................................................................................................................................ 217

Microprocessor Watchdog Timer ...................................................................................................................................................... 217

A/D Converter .................................................................................................................................................................................... 217

KPC-3 Plus Jumpers .......................................................................................................................................................................... 218

Appendix C: Options for the KPC-3 Plus .......................................................................................................................................... 221

Low Power Operation ........................................................................................................................................................................ 221

Expanding the RAM in the KPC-3 Plus ............................................................................................................................................ 221

Installing the Optional Real-time Clock Module ............................................................................................................................... 221

Replacing the Lithium Battery ........................................................................................................................................................... 222

Appendix D: In Case of Difficulty ...................................................................................................................................................... 223

KPC-3 Plus Does Not “Sign-On” to Computer ................................................................................................................................. 223

You Are Unable to Make a “Connect” .............................................................................................................................................. 223

Cannot Transmit................................................................................................................................................................................. 223

Cannot Return to Command Mode .................................................................................................................................................... 224

Appendix E: Additional Information ................................................................................................................................................. 225

Specifications ..................................................................................................................................................................................... 225

Messages from the KPC-3 Plus ......................................................................................................................................................... 226

ASCII Chart ....................................................................................................................................................................................... 232

KPC-3 Plus Parts List ........................................................................................................................................................................ 233

KPC-3 Plus Parts List ........................................................................................................................................................................ 233

KPC-3 Plus MX Parts List ................................ ................................................................ ................................ ................................. 234

KPC-3 Plus Parts Layout ................................................................................................................................................................... 235

KPC-3 Plus MX Parts Layout ............................................................................................................................................................ 236

9

LIMITED WARRANTY

KANTRONICS CO., INC.

LIMITED WARRANTY

Effective January 1, 1997

To receive notice of future updates, new product information and prompt warranty
service, please fill in the Kantronics Warranty Registration form COMPLETELY and
return it along with a copy of proof of purchase (to establish purchase date) by any
means to us (see our Contact Us page).Warranty Registration form and proof of
purchase may be e-mailed to [e-mail].

NOTE: Return of the Warranty Registration form and proof of purchase is a pre­condition to warranty coverage.

1. WARRANTY. Kantronics warrants to the first consumer purchaser (“you”), for the
Applicable Warranty Period (as described below), that the Applicable Product (as
described below) will be free from defects in material and workmanship.

2. REMEDY. Kantronics agrees that, for any Applicable Product found by Kantronics to
be in violation of the warranty of Section 1 hereof within the Applicable Warranty
Period, it will, at its option, repair or replace the defective Applicable Product at no
charge to you, excluding in-bound shipping charges.

3. EXCLUSIVE REMEDY. Repair or replacement of the Applicable Product, as
provided herein, is the sole remedy available to you against Kantronics, and in no
event will Kantronics be responsible for any other liability or damages or for
incidental, special, or consequential damages, regardless of whether purported
liability is predicated upon negligence, strict tort, contract, or other products liability
theory and whether or not Kantronics is warned about the possibility of such liability
or damages. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION

OF INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO THE ABOVE
LIMITATION OR EXCLUSION MAY NOT APPLY TO YOU.

4. DISCLAIMER. This Limited Warranty is in lieu of all other warranties expressed or

implied and no representative or person is authorized to assume for Kantronics any
other liability in connection with the sale of its products. KANTRONICS
SPECIFICALLY DISCLAIMS THE IMPLIED WARRANTY OF MERCHANTABILITY
AND IMPLIED WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE FOR
ANY APPLICABLE PRODUCT. IF, HOWEVER, YOU ARE A CONSUMER WITHIN
THE MEANING OF 15 U.S.C. 2301(3), THE ABOVE DISCLAIMER OF IMPLIED
WARRANTIES IS EFFECTIVE ONLY FOR PERIODS OUTSIDE THE APPLICABLE
WARRANTY PERIOD. SOME STATES DO NOT ALLOW LIMITATIONS ON HOW

LONG AN IMPLIED WARRANTY LASTS, SO THE ABOVE LIMITATION MAY
NOT APPLY TO YOU.

5. APPLICABLE PRODUCTS AND PERIODS. Kantronics products are of two types ­(1) hardware units and (2) firmware and software for operation of these units,
whether incorporated into the units themselves or separate from the units as

10

adjuncts or accessories to the units. Hardware units and the media containing
firmware, software and documentation are sold to the consumer purchaser and
become property of the purchaser. Firmware and software are licensed for use by
the consumer purchaser in return for a fee included in the purchase price of the units
and do not become the property of the consumer. (See separate License Agreement
provided with these products). The products to which the warranty of Section 1

hereof applies (herein “Applicable Products”) and the periods during which the
warranty shall apply to such products (herein, “Applicable Warranty Period”) are as

follows:

Applicable Products:

UNITS:

KPC-3 Plus, KPC-9612 Plus, KAM XL, MT1200, MT1200G

Applicable Warranty Period: One (1) year from date of purchase.

MEDIA:

EPROMS, CDs, manuals (however bound), specification and other
supplemental pages or any other media on which firmware, software or
documentation are supplied

Applicable Warranty Period: Thirty (30) days from date of purchase.

6. EXCLUSIONS. This Limited Warranty does not apply to the cosmetic appearance
of the Applicable Product; to broken or cracked cabinets; to any accessory not
supplied by Kantronics which is used with the Applicable Product; to any product
that has been subject to misuse abuse or overvoltage; to any product that has been
modified by non-Kantronics personnel unless specifically authorized in writing by
Kantronics; or to any product damaged or impaired by shipping (whether or not
caused by poor packaging), neglect, accident, wiring not installed by Kantronics,
improper parameter settings which are cleared by performing a hard reset, or use in
violation of instructions furnished by Kantronics or of generally accepted industry
practice. Kantronics does not warrant that the functions contained in any software
will meet your requirements or achieve your intended results; or that operation of
any software will be uninterrupted or error-free or without effect upon other software
used with it. Responsibility for the selection of the hardware and software program to

achieve your intended results rests with you.

7. REMEDY PROCEDURE. Should you need to make a warranty claim, first contact
the dealer from whom you purchased the product. If the dealer is unable to assist
you, contact us prior to returning an Applicable Product to receive a Return
Authorization Number. (As a practical matter, problems can often be solved in such
a manner without the product having to be returned to Kantronics for repair or
replacement.)

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Return of any Applicable Product for the enforcement of rights under this Limited
Warranty shall be at your expense. Any product returned for warranty service, which
Kantronics determines to be without defect or not covered by this Limited Warranty
shall be subject to the minimum charge for labor and the product will be returned to
you at your sole expense. Please note, no warranty service will be provided until
Kantronics has been furnished with your Warranty Registration card and copy of
proof of purchase establishing purchase date.

8. NON-ASSIGNMENT. This Limited Warranty is not assignable by you. Any attempt
to assign or transfer any of the rights, duties, or obligations hereof is void.

9. OTHER RIGHTS. This Limited Warranty gives you specific legal rights and
you may also have other rights, which vary from jurisdiction to jurisdiction.

12

Return/Repair Procedures

Important: Our repair statistics show that over 70 percent of the units returned for service do

not, in fact, require any service. Therefore, we advise you to please double-check the following
list of common, user-solvable, sources of difficulty before contacting Kantronics about returning
your unit for service.

Check-List for Possible Problems

Should you encounter difficulty in getting your equipment to “talk” to your computer, please
perform at least the following limited checks before calling or writing:

Carefully check your wiring connections to the 232 port.
If you purchased third-party cables, double-check to be sure that they conform to the

Kantronics’ wiring instructions in this manual.
Verify your terminal baud.

It may be useful to perform a “Hard Reset”. (See Hard Reset section.) If service or repairs still

appear necessary after you have checked the items listed above, it may be wise to call, fax, e­mail or write Kantronics to determine if the problem can be solved without returning the unit.

Return Procedures

When calling, report the product name and ask for the Service Department. Please have the
following information available:

The unit name and serial number (the serial number is found on the bottom of the unit).
The firmware version number (the version number is displayed when you give the Version

command).
If possible, you should have the unit and your computer available to perform troubleshooting

operations when you call.
The Service Department telephone hours are 8:00 AM to 12:00 Noon and 1:00 PM to 5:00 PM

Central Time, Monday through Friday. If you call outside these hours, the phone will just ring.
The service department telephone is not connected to the main switchboard and the
switchboard receptionist cannot transfer you to the service number. If lines are busy, you may
wish to (and it may be faster to) contact service by fax, or e-mail. Service e-mail is checked
twice per day. Before contacting us, please take the time to list out your problem fully and
carefully.

When writing, faxing, or e-mailing Kantronics, include a clear description of the problem, unit
name, firmware version, computer type, computer software used and if possible a list of
current parameter values for your unit (as shown in a DISPLAY listing). Be sure to include a
return fax number and/or e-mail address.

Returns to the factory for refund or exchange are strictly regulated. Any return for refund or
exchange, must be approved by the service department.

13

Charges

Consult the limited warranty policy in this manual for the service provisions offered by
Kantronics at no charge. This warranty is considered to be in force only when the customer
has submitted his completed warranty registration within 10 days of purchase, and when the
stipulations of the warranty have been met.

Violations of warranty clauses will automatically void the warranty and service or repairs will be
charged to the owner.

Service outside the warranty will be charged at the cost of parts, labor, and return shipping.
Units returned for service without a Return Authorization number will be subject to a minimum
charge of ½ h labor plus shipping and handling.

If payment has not been previously arranged, repaired (or un-repairable) units may be returned
via C.O.D.

These C.O.D. charges can be avoided by including your VISA or MasterCard number with your
unit to be repaired. Shipping and repair may then be charged.

International Returns



This section applies to international returns only, not to domestic returns.

In case of unit problems, first contact the dealer from whom you purchased the product. If you
must return a Kantronics product to us, please observe the steps outlined below. It will save you,
the customer, and Kantronics unnecessary difficulties and expense.



All returns must be shipped to the factory.



All expenses of returning items to Kantronics must be paid by you, including any duty/entry
fees, whether the return is for warranty or non-warranty repair.



Usually, the best way to return items to us is by mail. However, if you wish to use one of the
courier services such as DHL, UPS Expedited, Federal Express, etc., be sure to use DOOR-
TO-DOOR service. If you use one of these services, a commercial invoice may be required.
Please check with your carrier before shipping.



Include in the description of the items on the paperwork (whether postal or courier) the words:

“U.S. GOODS RETURNED FOR REPAIR/REPLACEMENT.”

Step 1. An additional description of “Amateur radio peripheral equipment”, or “Data

communications equipment”, would be helpful. It would also be helpful (but not required) to

include the code number 9801.00.1035 which tells U.S. Customs agents that the package

contains “U.S. goods returned without improvement/enhancement”. However, if the words
“U.S. goods returned for repair/replacement” are on the paperwork, the number is not really

necessary.

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 Provide a value for customs purposes. This is usually the value of the item(s) in their current

condition. A $0 value is not acceptable for U.S. Customs.

 Inside the package, with the item(s), include

 a fax number and/or e-mail address (if available) in case we need to contact you
 a correct and full address for return
 method of payment to be used for any charges (if MasterCard or VISA, include expiration

date)

 a brief description of the problem
 a reference to any conversations with the technical/sales staff about the problem
 and the Return Authorization number assigned

 For warranty repairs, we will pay the shipping charges to return the item(s) to you via air parcel

post. If you wish return by courier service, include your account number. To be eligible for
repair under warranty, we must have a record that you sent your Warranty Registration and
proof of purchase to Kantronics, and the item(s) must still be within the warranty period at the
time the return is authorized.

 For non-warranty repairs, you must pay the return shipping charges.

Radio Frequency Interference Statement

Note 1: This equipment has been tested and found to comply with the limits for a Class B

digital Device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide
reasonable protection against harmful interference in a residential installation. This equipment
generates, uses, and can radiate radio frequency energy and, if not installed and used in
accordance with the instructions, may cause harmful interference to radio communications.

There is no guarantee that the interference will not occur in a particular installation. If this
equipment does cause harmful interference to radio or television reception, which can be
determined by turning the equipment off and on, the user is encouraged to try to correct the
interference by one or more of the following measures:

 Reorient or relocate the receiving antenna.
 Increase the separation between the equipment and receiver.
 Connect the equipment into an outlet on a circuit different from that to which the receiver is

connected.
 Consult the dealer or an experienced Radio/TV technician for help.
The user is cautioned that any changes or modifications not expressly approved by the party

responsible for compliance could void the user’s authority to operate the equipment. The user

15

is also cautioned that any peripheral device installed with this equipment must be connected
with a high-quality shielded cable to insure compliance with FCC limits.

Note 2: The shield of the cable, whether foil, braid, braid over foil, or double braid, must be
properly terminated (connected) 360 to the connector. This is usually accomplished by the

use of a metal or metalized plastic back shell, but may be implemented by direct contact,
including soldering, with metal portion of connector. Experience has indicated that cable
assemblies (with connectors) advertised as “shielded” are not necessarily terminated properly,
if terminated at all. Check cable construction to be sure.

RFI Suppression

In moving to the world of digital communications via computers, a new dimension of RFI may be
encountered. In spite of the equipment manufacturers’ diligence, each new piece of electronic
equipment will react differently in each separate environment. Every amateur station will have its
own unique layout, equipment variation, and antenna installations. Experience has shown that
these differences are related to the total RF environment, and may be causative factors in RFI
induced problems. The suggestions given here may assist in resolving RFI problems you may
encounter in your “unique” station.

 Use shielded cable for all connections between equipment.
 Make all interconnecting cables as short as practical. A balance should be maintained

between cable length and equipment proximity. At times simply moving the video monitor

one foot further from an interface or other device will solve a “screen hash” problem.
 Antenna runs should be kept away from equipment control lines and/or interconnecting

cables. If it is necessary for such lines to cross each other they should do so at 90-degree

angles.

 Ground leads should be as short as possible and go to a GOOD EARTH GROUND.
 Interconnecting cables appearing to act as radiators or antennas should be looped through

a toroid. Be certain toroids, if used, are designed for the frequency in use.

16

FCC Declaration of Conformity:

NOTE: This equipment, Kantronics’ KPC–3 Plus, has been tested and found to comply
with the essential emission and immunity requirements of the EMC Directive FCC Title
47, Part 15, Subpart B. The test results are on file at the corporate offices of Kantronics.

Type of Equipment: Information Technology Equipment
Class of Equipment: Class B

CE Marking Considerations

The following cautions pertain to CE Marking of this product:

 All cables connecting to DC IN, PORT 1 (VHF), and COMPUTER must be  3 m

in length

 A cable for GPS or telemetry (control output or A/D input) connected to the

COMPUTER port may be  3 m in length.

 All cables, except for the DC IN port, must be shielded with the shield properly

terminated 360 to the connector. See note 2 in the RF Interference section

 The nominal 12 V dc power must be supplied from a CE marked or third party

approved power brick (wall wart) or ac to dc power supply. If a homemade power
supply is used the components making up the supply must meet IEC/EN
standards for such components.

17

Introduction

Welcome

Welcome to the Kantronics KPC-3 Plus, your pathway to amateur radio packet
communication.

Please review this chapter before you install your KPC-3 Plus as part of your packet
radio station.

Overview of This “User’s Guide” Manual

This user’s guide provides documentation on the KPC-3 Plus and packet radio,
including the following:

 What equipment you will need for your packet radio station.
 A brief introduction to packet radio.
 Installing and configuring your KPC-3 Plus packet radio station and making your

first connections.

 Getting started using your KPC-3 Plus.
 Documentation for each mode of operation of your KPC-3 Plus.
 A full “Command Reference”, documenting all KPC-3 Plus commands.
 Full details on KPC-3 Plus jumpers, a full parts list, and other technical

specifications.

Additional documentation and supporting material is available on the “Information and

Program” CD that ships with the KPC-3 Plus.

Major Uses of Your KPC-3 Plus

By adding the KPC-3 Plus and a computer to your ham radio station, you can send and
receive packets of digital information. This allows you to do the following:

 use computers to carry on real-time digital conversations between stations
 send, receive, store and forward mail using a personal mailbox inside the KPC-3

Plus

 send and receive mail using a community bulletin board
 send and receive files
 get and re-transmit location data from Global Positioning System devices

18

 serve as a digipeater for other stations
 serve as a network node point for other stations, using KA-NODE and/or the

optional K-Net feature

And much more.

Package Contents

Check to see that you have the items listed below (later you will see how these items
are used in your system):

 KPC-3 Plus unit
 parts to use in assembling cabling

 Male DSUB-9 connector for radio port
 Metalized DSUB-9 back shell with hardware
 3 foot (0.91 m) piece of 5-conductor shielded cable to connect the KPC-3

Plus to your radio

 2.1 mm dc power connector

 and, of course, this “User’s Guide” manual on a CD-ROM

Additional Parts for Your Packet Radio Station

In addition to your KPC-3 Plus unit, you will need the following parts to set up your
packet radio station:

 An FM transceiver
 A microphone (Mic) plug and/or mating accessory plug or external audio plug for

your radio

 A computer with an RS232 serial port (or other RS232 terminal device)
 A serial modem cable, used to connect the KPC-3 Plus to your computer
 A 12 V dc power supply or power adapter
 (optionally) 9 V battery and battery clip (not supplied, you must install)

19

Our Assumptions about You

We assume that you are familiar with the following or that you can get help on these
topics if necessary:

 general familiarity with your radio equipment and its intended uses
 basic use of your computer and its operating system, including copying disks and

files, working with directories, and identifying and using the serial (COM) ports on
your computer

 basic electronics needed if you are going to build or upgrade hardware yourself,

(e.g., making cables)

Documentation Conventions

The following conventions are used in the KPC-3 Plus documentation:
To indicate a particular key, the name of the key is given in capitals. For example, press

the ENTER key.
Sometimes you need to hold down one key on the computer while pressing another

key. This is indicated by giving the name of the first key, then a plus ‘+’, then the name

of the second key. For example, “Ctrl+C” means “press the key labeled ‘CTRL’ or ‘Ctrl’

(i.e., the “control” key) and, while continuing to hold it down, press the ‘C’ key”. Multiple-

key combinations that generate a single character are shown in angle brackets, like this:
<Ctrl+C>.

Conventions for the KPC-3 Plus commands are covered in the “Command Reference”
section of this manual.

Overview of Packet Radio

This section gives a brief overview of packet radio, for those who are new to packet
radio and those who want to review the topic.

Topics covered are:

 The three basic components of a packet radio station
 Sending a message from one station to another
 Details about packets
 A brief discussion of protocols
 An overview of the insides of the KPC-3 Plus

If you are already familiar with packet radio, you may wish to skip the rest of this
chapter, or give it a quick review.

20

Packet radio gives you the ability to send essentially error-free digital communications
to other packet radio stations. As a sender or receiver, you see just the messages, or
files, being sent and received. But there is much going on beneath the surface. You will
get more out of packet radio, and have an easier time getting started, if you have at
least a basic understanding of what is involved in packet radio communication.



Do not be concerned here with how to do things —that comes later.

Three Basic Components of a Packet Radio Station

A packet radio station has three basic parts:

 a transceiver, with an antenna,
 a device called a TNC (i.e., Terminal Node Controller), which is a combination

modem and special-purpose micro-computer, and

 a general purpose computer (or a terminal).

The three parts of a packet radio station work together as follows:



The transceiver: (1) sends and receives radio signals to and from your antenna
and (2) passes audio signals back and forth between itself and the TNC.



The TNC (Terminal Node Controller): (1) translates audio signals into digital
information and vice versa, (2) performs a number of control and information
storage functions, and (3) communicates digitally with your computer.



The computer communicates digitally with the TNC, so you can: (1) view
messages received from the transceiver or stored in a mailbox (i.e., PBBS), (2)
use the computer to send data to, and receive data from, other stations, via the
TNC and your transceiver, and (3) control the operation of the TNC.

Sending a Message to Another Station

A quick way to see the basic components of packet radio in action is to follow a simple
message as it goes from one station to another, via an intermediate station.

Let’s assume that an originating station, WØXI, wants to send the message “HELLO” to

a destination station, KBØNYK. Also, assume that WØXI knows that his signal might not

Antenna

KPC-3 Plus

TNC

Terminal Node Controller

Transceiver

Computer

21

reach KBØNYK’s station directly, but that it can be picked up and repeated by an

intermediate station, NØGRG, and then received by KBØNYK.
The following are the basic steps of a station-to-station packet communication, as seen

from the point of view of the message, “HELLO,” sent from source station WØXI to
destination station KBØNYK, through intermediate station NØGRG. Step 1 is one-time
configuration task, Steps 2-3 establish a connection between stations, and Steps 4-13
follow the “HELLO” message from the time it is created by WØXI to when it is read by
KBØNYK.

Step 1. Before this message can be transmitted from a source station to a destination

station, via an intermediate station, all the stations involved have to have
callsigns, which are used by the TNCs involved to identify and process
information (e.g., source, destination, and routing of information).

So we start by assuming each operator involved in this example has already
performed this one-time configuration task, creating the callsigns given
above. Stations are identified by reference to their callsigns. Note that a
callsign can be for a TNC (e.g., KPC-3 Plus) or for a Personal Bulletin Board
System (PBBS) “mailbox” that resides in RAM inside the TNC.

Step 2. This communication begins when the operator of station WØXI turns on his

computer, TNC (e.g., a KPC-3 Plus), and transceiver of his station and uses a
computer software program to tell the TNC that he wants to establish a line of
communication, called a “connection,” with a “destination” station KBØNYK
using an intermediate station NØGRG as a repeater station to carry the
information beyond the range of the originating station and into the range of
the destination station.

Step 3. The “connect” command with address given to the TNC causes the TNC to

formulate a “request to connect” message that is sent from WØXI. If this
message is detected by the specified intermediate station (i.e., NØGRG),
repeated, and then detected by the destination station (i.e., KBØNYK), a
connection may be established.

To confirm a connection, the destination station automatically sends a special
message back though the reverse path, to the originating TNC.

When this “confirmation of connection” is processed by WØXI’s TNC, the

TNC assumes that the operator wants to begin sending messages. So the
TNC: (1) puts a message on the computer monitor confirming that WØXI is
now connected, through intermediate station NØGRG, to KBØNYK, (2) turns

ON the “connected” indicator on the TNC, which stays ON as long as the

connection is in effect, and (3) switches itself from taking commands from the
computer (i.e., TNC in “command mode”) to serving as a message-processor,
sending and receiving messages to and from the connected stations (i.e.,
TNC in “conversation mode”).

22

Step 4. Now that WØXI is in “conversation” mode, the operator types in the message,

“HELLO”, and presses the ENTER key on the computer to indicate the end of

the message and the beginning of the message’s journey.

Step 5. The computer sends the message, “HELLO,” to the TNC for processing.
Step 6. The TNC receives the message, “HELLO”, and takes charge of the situation,

performing a number of complex operations: it uses the “connection”

information about where the message is to go and the path it is to take and
combines this with the message itself to assemble a “packet” of digital
information for transmission from the transceiver.

The details of what is in the packet and how it is organized are fully defined
by agreed-upon standards, so any machine that knows the “rules” can make
use of the information.

The standard for amateur packet radio at this time is AX.25, so let’s assume
the packet assembled in the TNC is an AX.25 packet.

Technical note: All amateur radio packets use the AX.25 standard, but it is
possible to use another standard or protocol (e.g., TCP/IP) “on top” of AX.25,
in which case the packet is referred to by the name of the highest-level
protocol.

Step 7. After the TNC assembles the “HELLO” message into a packet of digital

information in the TNC, it passes the packet on to a modem, which is also in
the TNC, which transforms the information into a series of audio signals for
serial transmission to station WØXI’s transceiver.

Step 8. The TNC orders the transceiver to send a message (i.e., keys push-to-talk)

and then sends the audio version of the “packet” through the radio port of the

TNC, up a cable to the microphone connector on station WØXI’s transceiver,

and to the transmitter.

Step 9. The packet is transmitted by WØXI’s transceiver as a burst of radio-frequency

signals.

Step 10. The “HELLO” packet, including address information (i.e., to, from, via) and

other control information, is now on the air, where it may be correctly
interpreted by all appropriately configured (i.e., AX.25 packet) stations that
receive the signal.

Step 11. KBØNYK is on the air and is running AX.25 packet, but it is too far away from

WØXI to pick up the signal, so does not get the message as it is sent from
WØXI.

Step 12. As we know from the “connection,” already established, intermediate station

NØGRG, an AX.25 packet radio station, is on the air, and is close enough to
receive the radio burst sent by WØXI. It receives the burst of radio signals
from WØXI and passes the audio signals on to its TNC for processing. The
TNC (e.g., a KPC-3 Plus) transforms the signal from audio to digital, analyzes

23

the series of 1’s and 0’s in the incoming bit-stream, and identifies the burst as
an AX.25 packet of information containing the message, “HELLO.”

Also, and most significantly, NØGRG registers that the packet designates
NØGRG as the first (and only) intermediate station on a path between a
source, WØXI, and a destination, KBØNYK. As a fully functioning AX.25
packet station, NØGRG knows what to do: it sends the message back out
over the air (i.e., digipeats it), where it may or may not be received by its
intended destination, KBØNYK. Before doing so, it marked its call in the
packet to indicate to others that it had seen the packet and had sent it on its
way.

Note: Since a “connection” has been established, we expect the message to

get through, but each packet is processed separately, and each must make it
on its own.

Step 13. As we know from the “connection,” already established, KBØNYK, an AX.25

packet radio station, is on the air, close enough to receive the RF burst sent
by NØGRG, and currently set to display messages on a computer screen. So
the “HELLO” message re-transmitted by NØGRG arrives at KBØNYK’s TNC
(e.g., a KPC-3 Plus), where it is processed and recognized as an AX.25

packet addressed to itself. Then KBØNYK’s TNC sends the message,

“HELLO,” to the computer screen for KBØNYK to read. At the same time,

KBØNYK’s TNC creates an acknowledgment packet to send back to WØXI’s
TNC, reversing the address path it found in the “HELLO” packet. When
KBØNYK’s TNC detects that the radio channel is clear, it keys the transmitter

and sends the packet back over the air.

Step 14. NØGRG’s TNC now recognizes another packet which has its callsign in the

address path, requesting it to be digipeated. NØGRG’s TNC does so as soon

as it can.

Step 15. WØXI’s TNC now hears a packet addressed to it. Since the digipeated packet

originally came from KBØNYK, to whom he is connected, and since the
packet contains an acknowledgment for data that he had recently sent,

WØXI’s TNC can rest easy knowing that the data he sent was properly

received.

This concludes our close-up look at a single packet communication event, showing how
the various parts of packet radio work with each other. To simplify and focus this
example, various details and possible complications were ignored, but this still shows
the basic steps involved in establishing a connection and sending the message
“HELLO” from one person/station to another person/station.

This example covers one of many uses of packet radio. As covered in other sections of
this manual, there are many ways to communicate with other stations.

Now that you have followed one particular message from one station to another, it is
useful to learn about the “packets” in packet radio.

24

Packets: Dividing Messages into Segments

An efficient way to send a message from one place to another is to break the
information into small segments, called packets or frames, and send each packet
separately.

Note: The correct technical term is “data frame”, not “packet” or “frame,” but we will use

the term “packet,” since that is familiar to most people and is common in the field.

Your packet radio station automatically divides your communication (e.g., a message or
file) into small segments (see the PACLEN command for details) and puts each

segment into its own “packet”. Each packet includes information used for addressing

and error correction.

Unconnected Packets

Packets do not need to be addressed to any particular station. Packets transmitted

without any established connection between sender and receiver are “unconnected”

packets. “Unconnected” packets are just sent out without any back-and-forth

coordination with any receiving station. Stations receiving these packets can check to
see if the packets are correct (i.e., the same bit pattern is received as when they were
sent), but they cannot request any retransmission of faulty packets. Nor can they
request re-transmission of any packets in a series that are not received at all. This is

because “unconnected” packets do not include sequence information that could be used

to track them in order and also because a TNC sending or receiving “unconnected”
packets is not set up to do any communicating about the success or failure of its packet
transmissions.



Note: Packets sent as “unconnected” are also called UNPROTO (non-protocol),
because the sender expects no response from the receiving station.

Connected Packets

Packet radio communication is often done between two stations that are connected

together. “Connected” communication using packet radio assures transmission with

virtually 100% accuracy by having the sender and receiver follow a set of rules for
communicating. These rules are specified in the AX.25 protocol.

The following is an overview of what happens during a packet radio communication
between two connected stations.

After a connection has been established between two stations, information Packets are
transmitted one-by-one (or in small batches), with a sequence number as part of each
packet, from the sending station to the receiving station. As the communication
proceeds, the receiving station keeps track of which packets it has received error-free
(as determined by using the check-sum that is part of each packet) and uses this to tell
the sending station what packet(s) to send next.

Using these rules of communication, a packet radio connection between a sender and a
receiver provides virtually error-free transmission of information, until the

25

communication is ended by the parties, or until the sender “times out” after trying a

number of times to get feedback and not succeeding.



Hint: In most cases, communication by packet radio is like mail, not the telephone,
in that it is not done in real-time, but via messages that are routed from one station,
or “node,” to another.

How a Packet is Organized

Your packet radio station takes care of all the details of working with packets, so you do

not need to see the “inside” of packets. But it is useful to have at least a basic idea of

how they are organized.

All amateur radio packets (also called “frames”) are defined by the AX.25 protocol,

which is discussed in the next section. Packets used to carry messages, or chunks of

messages, as in the “HELLO” example, are called “information packets.”

The following diagram shows the basic building blocks of “connected information”

packets used in amateur packet radio:

Kinds of Packets

As shown in the above diagram, the “control” field in an AX.25 packet includes a code

telling what kind of packet the current packet is. In addition to connected information
packets, the AX.25 protocol also defines two other kinds of packets, each of which is
nearly identical in structure to the connected information packet: control packets (of

Flag

Address

Control

PID

Data

Checksum

Flag

Single character for
“beginning of packet”

Destination station, Source station,
And up to 8 intermediate stations

Kind of packet, packet number,
and other control information

Optional Data with protocol ID
Data may have 1 to 256 bytes

16 bits derived from this

packet used to check for

errors in transmission

Single character for
“end of packet”

26

which there are several kinds) and unnumbered packets. To learn more about these,
see the documentation for the KPC-3 Plus’ MCOM command.

As noted at the beginning of this section, the organization of amateur radio packets is
defined by the AX.25 protocol. Now it is useful to give a brief discussion of this protocol,
and another that fits “within” it.

Protocols: Rules for Working Together

Packet radio, like any communication, is only possible if all parties involved (i.e., sender,
receiver, and intermediate points on the route between them) agree on the rules for
organizing information and the rules for dealing with all steps of the transmission. These
rules are called “protocols,” or standards.

AX.25

The defacto standard protocol for amateur packet radio communication is AX.25 (level
2, version 2). For details on AX.25, see the ARRL publication, AX.25 Amateur Packet-

Radio Link-Layer Protocol.



Hint: You can set the KPC-3 Plus to use an earlier protocol, AX.25 (level 2, version

1)

Alternatives to AX.25

TCP/IP and the KISS protocol: The TCP/IP (Transmission Control Protocol/ Internet

Protocol) suite of protocols require functionality not found in native AX.25 packets, so
Phil Karn KA9Q defined a protocol called KISS that implements TCP/IP functionality for
amateur radio. For further information on KISS see the KISS Mode section of the
“Modes of Operation” chapter.

XKISS is an extension of the KISS protocol, defined by John Wiseman G8BPQ.

For further information on XKISS, see the XKISS Mode section of the “Modes of

Operation” chapter

.

27

Inside a TNC – the KPC-3 Plus

To better understand the workings of your packet radio station, it is helpful to have an
overview of the major components of the TNC device at the center of your station.

In the early days of packet radio, TNC’s consisted primarily of a modem for
communicating with a transceiver and a special-purpose microprocessor called a PAD
(i.e., packet assembler/disassembler) used to process packets of information and
communicates with a computer or terminal.



As packet radio has developed, more and more features have been added, such as

memory and software dedicated to a “Personal Bulletin Board System” within the

TNC. The following diagram shows the most important internal components of a
TNC (the KPC-3 Plus). The diagram is not to scale. For a detailed example, see the
parts list and layout diagram for the KPC-3 Plus in the appendices of this manual.

Note: Other TNC’s may have different features than the KPC-3 Plus for example, the
ability to operate two radios at once.

28

This concludes the introduction to packet radio. The next chapter guides you through
the steps of installing your KPC-3 Plus.

Micro-processor

(optional)

Real Time

KPC-3 Plus Firmware/EPROM

Kantronics software,
stored in
“Electrically Programmable

Read-Only Memory”

* Programs to support

Interface modes
(ie Newuser,Terminal, Host

PBBS, Kiss, Xkiss, & GPS)

* Text for on-line Help

* Programs to support

other functions

(e.g., KA-NODES)

Modem

Lithium Battery:
power back-up for
RAM and optional
Real Time Clock

RAM (Random Access Memory)
The KPC-3 Plus ships with
128K of RAM, which may
be replaced by up to 512K of
RAM (e.g. to accommodate

a bigger PBBS Mailbox).

* Memory used for internal

functions (e.g. storing
parameter settings, assembling
and disassembling packets,
storing data from
packet connections,
KA-NODE support, and

Storing GPS tracking data

* Mailbox (PBBS) storage: Default

size is 100K (with 128K RAM).
User-configurable, within

limits of available RAM.

Inside the KPC-3 Plus

to computer and/or GPS device

to transceiver

29

Installing Your KPC-3 Plus

The goal of this chapter is to guide you as quickly as possible through the steps of
setting up your packet radio station.

The major steps involved in installing (i.e., connecting the parts) your packet radio
station are as follows:

 connect your KPC-3 Plus to a power source and confirm that the unit powers on

when it should,

 connect the “Computer” port on the KPC-3 Plus to a serial port on your computer,

install terminal communication software in the computer if necessary, and
configure the terminal software and the KPC-3 Plus so digital information can be
sent back and forth between the KPC-3 Plus and the serial port on the computer,

 connect the “Radio” port on your KPC-3 Plus to your transceiver and adjust the

volume of the transceiver, so the KPC-3 Plus can receive signals from the
transceiver for processing and the KPC-3 Plus can send signals to the
transceiver for transmission,

 (optionally) use the “Computer” port on the KPC-3 Plus to connect your KPC-3

Plus to a GPS device, so the KPC-3 Plus and the GPS device can send digital
information back and forth.

To show you where you are heading with the step-by-step configuration covered below,
we start with a brief section on equipment needs for your station and an overview
diagram that shows how the parts of your station will be connected when you are ready
to begin using it.

30

The Major Components of Your Station

This section describes the basic components needed for your packet radio station and
the connections between components that will be involved in the installation of your
station.

The KPC-3 Plus

Your KPC-3 Plus is going to be at the center of your packet radio station, so setting up
your station involves connecting other units to your KPC-3 Plus.

As shown below, the back of the unit has connectors to connect the KPC-3 Plus to your
transceiver, your computer (or a GPS device), and a power source:

Back Panel

Radio Port Computer Port Power Jack
DSUB-9 female DSUB-25 female 2.1 mm

Radio Port This DSUB-9 female connector accepts the cable from your

radio, for 1200 baud packet operation.

Computer This DSUB-25 female connector accepts the cable from your

computer serial port. The KPC-3 Plus communicates with
RS232 levels using standard ASCII characters for all
commands.

Power jack (2.1 mm) This connector is provided to apply external power (6 to 25 V

dc) to the KPC-3 Plus. The center post is the positive
connection and the sleeve is negative (ground).

Note: All Kantronics’ TNC's can operate without the computer being connected, once
they have been configured. For example, you can receive and store messages in the

31

personal mailbox inside the KPC-3 Plus without using your computer. And your KPC-3
Plus can serve as a relay station for other stations without your computer being
connected. This independence from the computer is possible because the TNC
contains the intelligence necessary to carry out these functions, once it is appropriately
configured and attached to a transceiver.

The Transceiver

Your KPC-3 Plus will operate with most FM transceivers.
There are currently hundreds of models of FM transceivers. You will need to refer to

the documentation for your transceiver to determine how it must be connected to
external devices, such as the KPC-3 Plus.

Specifically, you will need to know:

 what type of microphone connector to use with your transceiver, and
 which pins connect to which in the cabling between the KPC-3 Plus and your

transceiver’s microphone

Wiring diagrams for some common transceivers are included later in this chapter for
your assistance.

The Computer

Your KPC-3 Plus can work with any computer that can communicate with it through a
standard RS232 serial modem port.

Technical note: You need to be sure the wiring is as shown in the installation section
below. You may, of course, make your own cable; make sure it is correctly wired and
shielded.

The Serial Port on Your Computer

You will be using a standard (RS232) modem cable (or making a cable with the same
wiring) to connect your KPC-3 Plus to a serial (COM) port on your computer. The
connector needed at the computer-end of the modem cable has to fit the connector on
your computer’s serial (COM) port. Therefore, you will need to know the following:

1. Is your computer's serial (COM) port DSUB-9 or DSUB-25? (most contemporary
computer serial ports are DSUB-9 Male). The computer-end of your RS232 cable
must have the same number of terminals, as does your serial (COM) port.

DSUB-9 (9 pins) DSUB-25 (25 pins)

32

2. Note that your computer's serial (COM) port is male.

The computer-end of your RS232 cable must be female, to connect to the
computer's male serial (COM) port.



Hint: Since, the KPC-3 Plus’ “Computer” port has a female DSUB-25 connector, the
KPC-3 Plus end of your modem cable must have a male DSUB-25 connector.

Be sure the cable between your KPC-3 Plus and the computer is correctly wired. This
topic is covered when we get to the actual installation of the cable.

Technical note: To use your KPC-3 Plus with a non-PC compatible, use a serial
communication program and a serial modem cable (i.e., RS232 cable). You can get
help from your computer dealer, users group and members of the amateur radio
community. When talking with computer dealers or others who may not be familiar

with packet radio, refer to your KPC-3 Plus as an “external modem,” not as a
“TNC,” a less familiar term.

GPS Device (Optional)

The KPC-3 Plus works with Global Positioning System (GPS) devices that (1) support
the NMEA 0183 standard and (2) have a dataport through which they communicate.
The GPS device connects to the KPC-3 Plus through its serial (“computer”) port, or
alternately, through a pin on its “Radio” port.

Note: The GPS data port must be RS232 compatible to mate with the KPC-3 Plus.

33

How the Parts of Your Station are Connected

The following diagram shows how the components of your KPC-3 Plus packet radio
station will be connected and the kinds of connectors that will be used. As you
assemble your station, you may wish to refer to this diagram.

With this overview, we are now ready for step-by-step instructions for installing your
station, which we will do in the following order:

 The three different ways you can power the KPC-3 Plus
 The RS232 connection between your KPC-3 Plus and your computer
 The cable assembly connecting your KPC-3 Plus to both the speaker jack and

the microphone of your transceiver

 (Optional) The connection between the computer port on your KPC-3 Plus and a

GPS device

As we go through the steps of setting up your station, we will shift from hardware to
software issues and back, since your station needs to be set up both in terms of
hardware and software.

34

Connect Your KPC-3 Plus to a Power Source

As illustrated on the right side of the station cabling diagram on page 33, there are three
ways to supply power to your KPC-3 Plus.

 You may use external power by connecting the KPC-3 Plus to a 12 V dc source

on your bench

 You may use external power by connecting the KPC-3 Plus to a 120-V ac power

source using a 12-V dc adapter. Or use a 230-V ac 50-Hz to 12-V dc adapter if
your mains are such.

 You may use internal power by installing a 9-V battery inside the KPC-3 Plus (as

explained below, before doing this you need to install a battery clip (pig tail)
inside your KPC-3 Plus).



See Appendix E for the allowed range of voltage inputs.

The steps needed for each way to supply power to the KPC-3 Plus are given below,
along with detailed specification for each part needed. Of course, the parts you need
depend on which option(s) you use.



The KPC-3 Plus ships with LEDs ON, so the Power indicator (LED) will turn ON
when power is ON. If the LED value has been switched to OFF, the Power LED will
just blink once, briefly, when power is applied.

External Power from Your Bench (12 V dc)

Here, you will use a 2.1-mm power plug and 18-22 gauge stranded 2-conductor cable to
connect to a 12-V dc power supply on your bench. The steps are:

Step 2. Build a cable by attaching the supplied 2.1-mm power plug to a user-supplied

18-22 gauge stranded 2-conductor cable—connecting the center of the jack
to the positive terminal of the power supply and the shell of the power jack to
the negative terminal of the power supply,

Step 3. (1) Turn OFF all power, (2) attach one end of the bench-power cable to a 12-

V dc power source on your bench, and (3) plug the 2.1-mm power plug into
the “Power” connector of the KPC-3 Plus,

Step 4. Turn ON the power supply, (2) press the power switch on the front panel of

the KPC-3 Plus to turn your KPC-3 Plus ON, (3) confirm that the power
indicator next to the power switch goes on, and then (4) press the KPC-3
Plus’ power switch again to turn the power OFF.

 If the power indicator (LED) does not go on as expected, check to be sure the

wiring is correct. If you have checked the wiring carefully and the power indicator
still does not go on as expected, check or replace any fuses in line between the
power supply and the KPC.

35

Caution: Do not exceed the power specifications for the KPC-3 Plus (see
specifications).

If you elect to install a fuse in the positive lead, do not use a fuse of greater than 200­250 mA.

External Power Transformed from 120-V ac Mains

You can use external power from a 120-V ac power source after transforming the
external power to 12 V dc (using a class 2 transformer: input 120 V ac 60 Hz 6 W;
nominal output 12 V dc 300 mA).

The steps are:
Step 1. You may order from Kantronics, as an option, a Kantronics 120-V ac to 12-V

dc 300-mA power adapter, or you may purchase the needed 120-V ac to 12-V
dc 300-mA power adapter from a third party,

Step 2. Connect the 2.1-mm connector on the assembly to the power connector of

the KPC-3 Plus and plug the power adapter into the 120-V ac power source
(being sure that the center is positive),

Step 3. Press the power switch on the front panel of the KPC-3 Plus to turn your

KPC-3 Plus ON, confirm that the power indicator next to the power switch
goes on, and then press the power switch again to turn the power OFF.



If the power indicator (LED) does not go on as expected, the unit may be defective,
so you should check with your dealer.

Internal Power, from a Battery.

For activities such as field day and back-packing, you can also install an internal 9-V
battery for power, after installing a battery clip on the printed circuit board of the KPC-3
Plus.

Note: Before installing a 9 V battery inside the KPC-3 Plus, you need to install a battery
clip (pigtail) and configure jumpers J1 and J2. First, purchase a 9-V battery clip (e.g.,
Radio Shack’s heavy-duty 9-V snap connector, part number 270-324). Second, solder
the clip leads to the battery pads on the printed circuit board (PCB). The pads are
labeled “+BATT-” and are located in the corner of the PCB near the power connector.
Make sure you solder the positive lead of the battery clip to the “+” pad, and be careful
not to damage any other connections on the PCB (use a low watt iron). Third, set
jumpers J1 and J2; defaults are J1 OFF (jumper on one leg only) and J2 ON (jumper on
both legs). In this position, the battery will power the TNC and will be cut off (by jack P3)
if an external power supply is attached. If you desire the battery to take over, i.e. run the
unit, in case the external power supply is plugged in but fails (or not turned on), then set
J1 ON and J2 OFF. In this configuration, whichever supply has the higher voltage
(battery or external supply) will power the TNC.

To use a 9-V battery for power, install the battery as follows:

36

Step 1. Open the KPC-3 Plus case
Step 2. Confirm that a battery connector (pig tail, snap connector) has been installed

or install one, as described above, if needed. If there is a protective clip over

the battery connector, remove it
Step 3. Attach a 9-V battery
Step 4. Close the case
Step 5. Press the power switch on the front panel of the KPC-3 Plus to turn your

KPC-3 Plus ON, confirm that the power indicator next to the power switch

goes on, and then press the power switch again to turn the power OFF
If the power indicator (LED) does not go on as expected, the unit may be defective, so

you should check with your dealer.
This concludes the installation of power to your KPC-3 Plus. The next topic is

connecting your KPC-3 Plus to your computer.

Connect your KPC-3 Plus to Your Computer

Your KPC-3 Plus and your computer communicate with each other via a serial
communication cable connecting the KPC-3 Plus’ “Computer” port and a serial (COM)
port on your computer. This connection is shown in the diagram on page 33.

Your Serial Communication Cable

The serial cable needed to connect your KPC-3 Plus to your computer (a standard off­the-shelf, RS232 modem cable) is not supplied with the KPC-3 Plus. You will need to
purchase one, or construct one.

Note: You may construct your own cable, using wiring instructions given below.
The two options, purchasing your cable or making it, are covered next.

Purchase Your Serial Cable

To purchase your cable (from your local amateur radio dealer or computer dealer):

 specify that you need a standard serial modem cable (RS232), with high quality

shielding (see Note 2 in the Radio Frequency Interference Statement section),
less than 3-m in length, and at least 9 wires connected,

 specify that one connector be a male DSUB-25 connector (to connect to your

KPC-3 Plus’ female “Computer” port) and the other connector be a female
DSUB-9 or DSUB-25 connector (depending upon whether your computer’s serial
(COM) port has a male DSUB-9 or DSUB-25 connector)

37

Make Your Serial Cable

This section is for those making your own cable instead of purchasing one.
We assume that if you are making your own cable you are familiar with the process and

just need to know: (1) what parts are needed, and (2) how the parts are connected.

Parts needed:

 a male DSUB-25 connector, to connect to the KPC-3 Plus’ (female) “Computer”

port,

 either a female DSUB-9 or a female DSUB-25 connector, depending on the

connector on your computer’s serial (COM) port, to connect to the computer’s

(male) serial (COM) port,

 an appropriate length of high quality shielded cable with 5 or more wires,

 as shown below, if you are using a DSUB-9 connector, either 5 or 8 wires can

be connected and any other wires are unused,

 as shown below, if you are using a DSUB-25 connector, either 5 or 9 wires

can be connected and any other wires are unused.
Note: You must terminate the shield on each end of the cable assembly properly. See

Note 2 in the Radio Frequency Interference Statement section.

Wiring instructions:



Some third-party software does not use hardware flow control and therefore does
not need the RTS and CTS wires shown below.

For details on preparing your cable wiring, use the chart below that is appropriate for
your configuration. In each case, there is a listing of which KPC-3 Plus (“Computer”
port) pin needs to be connected to which pin on the computer’s serial (COM) port. The
wiring depends upon whether your computer has a 25-pin connector or a 9-pin
connector, and on how many wires are in the cable (you only need 5 wires connected
for KPC-3 Plus operations, but you may connect more wires to use the cable for other
purposes). See page 209 for a diagram showing pin numbers on a DSUB-25 connector.

CASE 1-A: Wiring if computer has a 25-pin connector and the cable has 5 wires:
KPC-3 Plus Computer

2 <——> 2 TXD
3 <——> 3 RXD
4 <——> 4 RTS

38

5 <——> 5 CTS
7 <——> 7 SG

CASE 1-B: Wiring if computer has a 25-pin connector and the cable has 9 (or more)
wires. Same as in CASE 1-A, and also:

KPC-3 Plus Computer

1 <——> 1 FG
6 <——> 6 DSR
8 <——> 8 DCD

20 <——> 20 DTR
CASE 2-A: Wiring if computer has a 9-pin connector and the cable has 5 wires:
KPC-3 Plus Computer

2 <——> 3 TXD

3 <——> 2 RXD

4 <——> 7 RTS

5 <——> 8 CTS

7 <——> 5 SG
CASE 2-B: Wiring if computer has a 9-pin connector and the cable has 8 or more wires.

Same as in CASE 2-A, and also:
KPC-3 Plus Computer

6 <——> 6 DSR

8 <——> 1 DCD

20 <——> 4 DTR

Technical note for advanced users: Two of the first five wires in each chart above
(RTS and CTS) are used for hardware flow control, so if your program uses just
software flow control and not hardware flow control, you may not need to use these two
hardware flow control wires.



If you are not using a PC compatible computer, the wiring required between your
computer and your KPC-3 Plus is the same wiring you would use for an external
telephone modem. This cable should be available from your computer dealer.
Appendix A of this manual includes details on the functions of the KPC-3 Plus’ pins.

39

The software (terminal program) requirements are also the same as that used for a
telephone modem.

Installing the RS232 Cable

Once you have purchased or made your serial communication cable, connect it as
follows:

Step 1. Make sure that power to both your computer and your KPC-3 Plus is turned

OFF.

Step 2. Plug the male DSUB-25 connector end of the serial cable into the “Computer”

port of the KPC-3 Plus.

Step 3. Plug the female DSUB-9 or DSUB-25 connector end of the serial cable into a

serial port of your computer.

Caution: Be sure you do not connect to a parallel port instead of a serial port: the
KPC-3 Plus communicates serially, so it cannot communicate through a parallel port.
Computer’s parallel ports (i.e., printer, or LPT port) usually have female DSUB-25
connectors. Do not connect the KPC-3 Plus to a female DSUB-25 connector on the
computer unless you are sure it is a serial (COM) port not a parallel (LPT) port.

Step 1. Check the connectors at each end of the cable, and secure the connectors

using the mounting screws,

Step 2. Turn ON the power to your computer, in preparation for installing

communication software in the computer, but leave the KPC-3 Plus power
OFF.

Caution: for users of a 25-pin serial modem cable: As originally shipped, the KPC-3
Plus does not connect a power source to its serial port, but an advanced user can
change jumpers so that it does. If your KPC-3 Plus has been altered to apply 12 V dc to
pin 13 of the computer (serial) port, this can DAMAGE your computer if pin 13 is wired.
To check to see if your KPC-3 Plus has been changed in this way, see the section on
jumpers in this manual. Note that the factory default setting of the jumper does not
connect pin 13.

This concludes the physical installation of the serial cable needed for your KPC-3 Plus
and your computer to communicate with each other.

To verify that your serial cable is correctly wired and connected, you need to install
communication software in the computer and then use that software to establish
communication with the KPC-3 Plus.

Configure Your KPC-3 Plus

After connecting your KPC-3 Plus and your computer with an RS232 serial modem
cable, you are ready to:

40

 install and start terminal software in your computer to enable communication

between your KPC-3 Plus and your computer,

 use the terminal communication software to establish communication with your

KPC-3 Plus, including setting the speed of communications back and forth, and

 configure your KPC-3 Plus to prepare it for your use, including giving the KPC-3

Plus your CALLSIGN and setting KPC-3 Plus parameter values.

HyperTerminal

To communicate with the KPC-3 Plus, all you need is a basic terminal communication
program. Windows systems (from Win95, up to WinXP) come with one called
HyperTerminal. There are several other terminal programs, which can be used on
Windows computers and on other operating systems. Following the instructions for
HyperTerminal will give you the basics for setting up other terminal programs.

To start HyperTerminal in Windows, click Start, Programs, Accessories,
Communications. HyperTerminal should be one of the possible selections. If it is not, it
may not have been installed when Windows was installed. You will then have to use the
Add Program, Add Windows Component from the Control Panel to install it.

Click HyperTerminal from the Accessories menu. HyperTerminal will open with a
window asking for a name for a new connection. Enter “KPC-3Plus9600”. Pick a
different icon if you want, then click OK.

A “Connect To” window will now open. Use the drop down menu under “Connect using:”

to select COM1. Then click OK.

A “COM1 Properties” window will now appear. Select 9600 bits/s, 8 data bits, no parity,

1 stop bit, and hardware flow control. Click OK.

You should now be at the main HyperTerminal screen. Click “File”, then “Properties”. In
the Properties window, select Settings. “Terminal keys” and “CTRL+H” should already

be selected. Use the drop down menu under “Emulation:” to select “TTY”. “Terminal

Setup” will allow you to change your cursor; “Use destructive backspace” should be
checked. Under “ASCII Setup” the defaults are sufficient (delays of 0 and only “wrap

lines” checked). Click OK to close the Property windows.

You should now be back at the main HyperTerminal screen. Click File, then Save. The
next time you click Start, Programs, Accessories, Communications, you will see that
there is a HyperTerminal menu with a selection for “KPC-3 Plus 9600.ht”. Clicking this
will get you immediately to the main HyperTerminal screen already set up for the KPC-3
Plus.

Later you may wish to change the baud or com port you are using with the KPC-3 Plus.
Before you can do that in HyperTerminal, you will first have to tell HyperTerminal to

“disconnect”; there is a button on the HyperTerminal screen to do that, looking like a

phone being hung up. Once disconnected, you can use the Properties menu to change
the HyperTerminal configuration.

41

Now turn on the KPC-3 Plus.

AUTOBAUD

The first time your KPC-3 Plus is used, it runs an AUTOBAUD routine to assure that the
KPC-3 Plus baud is the same as that of whatever communication software you are
using.

The KPC-3 Plus’ AUTOBAUD routine works as follows:

Step 1. AUTOBAUD sends and resends the message “PRESS (*) TO SET BAUD”

at one baud after another. When the KPC-3 Plus’ baud matches that of

your terminal program, you can read this on your screen; if the two rates

do not match, the message appears garbled, if it appears at all.

Step 2. Any time while this message is being sent, whether it is readable or

garbled on your screen, enter the “*” character (SHIFT+8 key

combination).

Step 3. When the AUTOBAUD routine receives, the “*” character from the serial

port, it uses that character to determine the baud in use.

Step 4. AUTOBAUD then sets the KPC-3 Plus’ baud (ABAUD) to match the baud

used.

Technical note: The KPC-3 Plus’ Baud is stored in the KPC-3 Plus as the value
of the ABAUD parameter, so when you use the KPC-3 Plus later, it will start with
that baud. This is made possible by an internal lithium battery supplied with the
KPC-3 Plus. Later, you can change the TNC baud if you want, as long as you
change your terminal’s baud to match.

Step 5. Finally, AUTOBAUD sends a “sign-on” message and asks for the user’s

CALLSIGN, which will also be stored in the KPC-3 Plus and used until

changed. At this point, the user is ready to give commands to the KPC-3

Plus.



Hint: Do not confuse the KPC-3 Plus’ baud for serial communication on the
computer port with the KPC-3 Plus’ 1200-baud for communicating using the radio
port, which is connected by a custom-wired cabling to a transceiver.

Setting Basic Communication Parameters

There are several KPC-3 Plus settings in addition to ABAUD (baud) and MYCALL
(CALLSIGN) that you may wish to change, especially if parameter values in your KPC-3
Plus have been changed from their default settings. Even if you do not want to change
anything now, knowing about these parameters and knowing how to reconfigure your
KPC-3 Plus gives you more control in using it with HyperTerminal.

42

Required TNC Parameter Settings

The following TNC parameter settings are needed:

 COMMAND = $03 (CTRL+C) (default = $03, so unless this has been changed,

you do not need to do anything).

 CANLINE default = CTRL+X (HEX $18)
 CANPAC default = CTRL+Y (HEX $19)
 PASS default = CTRL+V (HEX $16)

Optional Parameter Settings

The following TNC parameters are generally used with their default settings when
running HyperTerminal, but you may wish to change them. If they have been set to non­default values, you may wish to change them back.

 ECHO = ON (default)
 FLOW = ON (default)

Technical note: Usually, ECHO and FLOW go together, both ON or both OFF.
When using software that supports split screen displays, for example, set both
ECHO and FLOW to OFF.

 XFLOW = ON (default)

Technical note: XFLOW controls whether or not software flow control is ON. If
XFLOW is set to OFF, the following parameters should also be set to 0 (zero):
XON, XOFF, START, and STOP.

 FILTER = OFF (default)
 8BITCONV = ON (default)



Hint: Also, the MONITOR parameter may be ON or OFF (default = ON). You may
have Monitor ON while using HyperTerminal. But to prevent a build-up of data in an
internal buffer in the TNC, you should turn Monitor OFF when exiting HyperTerminal
and leave the TNC ON. This is because when the TNC’s receive buffer is full, your
station will give a BUSY signal to other stations that try to connect.

Trouble-Shooting Difficulties in Communicating

If you are having difficulty establishing and maintaining communication between
HyperTerminal and your TNC, here are some points to consider.

43

Problem: Go to Terminal Screen, but Nothing Happens

One possibility is that the current COM port does have a device on it, but it is not a
TNC. It might be a mouse or an internal phone modem, for example. To see if it is a
mouse, go to the TERMINAL Screen, start moving your mouse and see if sequences of
characters appear as you move the mouse. If so, change the COM port setting in
HyperTerminal and try again.

Another possibility is that the KPC-3 Plus has already been programmed with a different
baud than the one set in the terminal program. You can try changing the baud in the
terminal program, or you can use the self-test jumper (J11) to erase the current settings
in the KPC-3 Plus, forcing the KPC-3 Plus to try its Autobaud routine.

Problem: You Are Getting Bad or Intermittent Data

Many PC compatible computers are designed with a built-in potential conflict that may
cause a problem. Both COM2 and COM4 (and both COM1 and COM3) may use the
same interrupt (IRQ) mechanism to get the attention of the computer. This means that if
devices on both COM2 and COM4 (or both COM1 and COM3) are sending signals to
the computer at the same time, this can cause problems for programs, such as
HyperTerminal, that use either COM port. If you are getting bad data, check to see if
you have another device that might be getting confused with your TNC (on COM4 if
your TNC is on COM2; COM3 if your TNC is on COM1) and make it inactive or remove
it while using HyperTerminal with your TNC.

Problem: Your TNC Stops Behaving Normally

HyperTerminal is intended for use with a TNC in NEWUSER or TERMINAL Interface
Mode (or, less often, in BBS or GPS Interface Mode), but it may receive data from the
TNC in any Interface Mode. Non-response, garbled data, or partially garbled data may
indicate the TNC has been switched to HOST or KISS mode and needs to be switched
back to NEWUSER or TERMINAL. See the TNC documentation for instructions on how
to determine what Interface Mode your TNC is in currently and how to change it to the
Interface Mode you want (NEWUSER or TERMINAL).

Connect the KPC-3 Plus to a Transceiver

The last connections you need to establish are between your KPC-3 Plus and your
transceiver. You will construct and install a transceiver cable assembly that has two
functions: (1) to send signals from the speaker jack of your transceiver to your KPC-3
Plus’ “Radio” port for processing, and (2) to send signals from your KPC-3 Plus’ “Radio”
port to the microphone connection of your transceiver for transmission.

As illustrated in the diagram on page 33, the transceiver cable connects to the “Radio”
port on the KPC-3 Plus via a male DSUB-9 connector shipped with your KPC-3.

This section goes step-by-step, dealing with the following questions:

 What parts will be needed for the assembly?

44

 What are the exact wiring requirements for connecting your transceiver to the

KPC-3 Plus, as determined by information given in this document and also by
requirements for your own particular make and model of transceiver (as
determined by the documentation for your transceiver)?

 What are the steps used in constructing and connecting the cable assembly?
 Once the cable is in place, how does one set the volume level of the transceiver

for optimal performance?

Parts for Connecting the KPC-3 Plus to a Transceiver

The following parts (shipped with your KPC-3 Plus unless otherwise noted) are needed
for constructing the cable assembly that will connect your KPC-3 Plus and your
transceiver:

 DSUB-9 connector kit (including hardware), to make the DSUB-9 connector for

the end of the transceiver cabling that connects to the KPC-3 Plus’ “Radio” port

 A 3-foot (0.91 m) length of 5-conductor shielded cable, to connect a user-

supplied microphone connector (i.e., the Mic plug) and/or a user-supplied
auxiliary connector (plug) or external audio connector (plug) for your transceiver
to the DSUB-9 connector supplied with your KPC-3 Plus

Preparing the Transceiver Cable Assembly

This section gives instructions for how to assemble the cable assembly needed to
connect your transceiver to your KPC-3 Plus, starting with the wiring requirements.

Wiring Directions (Connecting KPC-3 Plus and Transceiver)

You will need to determine which pins on your DSUB-9 connector will be wired to which

connections on your particular transceiver’s microphone connector and speaker jack.

Wiring directions are covered after the following examples of typical transceivers,
including handhelds.



There are many different models of transceivers, each with their own exact
requirements for how they are to be connected to devices such as a KPC-3 Plus.
While the following examples will help, you will need to refer to your transceiver
documentation (or transceiver dealer) for exact instructions on which connections
you need to make as you wire your transceiver cable assembly.

Note: If you need further assistance on your radio cabling, contact the radio
manufacturer, your dealer, or a local amateur who has already installed a TNC.
Kantronics is not likely to have pin assignments for specific transceiver models.

The following diagrams, used for example only, show wiring connections between the
male connector for the KPC-3 Plus’ “Radio” port, and common transceivers (including
HTs) from three major manufacturers: Yaesu, Icom, and Kenwood.

45



These diagrams may also apply to transceivers from other manufacturers, but you
need to check to be sure how your transceiver needs to be wired. See the section on
“Interfacing Hand-Held Radios” in the “Advanced Installation” appendix for further
information.

46

47

48

Your Transceiver’s Microphone Connections to the KPC-3 Plus.

For the microphone on your transceiver, you may wish to make notes of the following
connections, which you will use, for wiring your assembly:

 identify and make a note of the microphone input (which will be wired to pin 1,

transmit audio on the KPC-3 Plus’ DSUB-9 “Radio” port),

 identify and make a note of the PTT or STBY connection (which will be wired to

pin 3, Push-to-Talk on the KPC-3 Plus’ DSUB-9 “Radio” port),

 for base or mobile (but not hand-held) transceivers, identify and make a note of

the ground connection (which, optionally, may be wired to pin 9, one of the
ground pins on the KPC-3 Plus’ DSUB-9 “Radio” port, or left unconnected).

Your Transceiver’s Speaker Jack Connections to the KPC-3 Plus

For the speaker jack on your transceiver, make a note of the following connections,
which you will use for wiring your assembly:

 identify and make a note of the connector to your external speaker plug (which

will be wired to pin 5, receive audio on the KPC-3 Plus’ DSUB-9 “Radio” port),

 identify and make a note of the connector to your external speaker plug (which

will be wired to pin 6, one of the ground pins on the KPC-3 Plus’ DSUB-9
“Radio” port).

Constructing the Cable Assembly

As you construct the cable assembly, it may be helpful to refer to the diagram on page

33.
Important: As shown in the diagram immediately below, looking at the rear panel, the

pins in the KPC-3 Plus’ female DSUB-9 “Radio” connector are numbered from the
upper right (pin 1) to the lower left (pin 9). As you connect wires to pins on the DSUB­9 connector on your cable, you need to be sure to connect to the correct pins.

As shown in the diagram below, if you look at the solder side (wiring side) of the male
DSUB-9 connector, the pins are numbered (again) from upper right (pin1), to lower
left (pin 9).



Similarly, when working with a typical 8-pin Mic connector where you know the pin
numbers of pins, you need to consider which way you are looking at the connector
(looking at pins/sockets or looking at the wiring side, where the wires are actually
connected).

49



Hint: Make notes of which wires (colors, cables) you use for each connection, so you
will be able to keep track of which connection is which.

To construct your transceiver cable assembly, proceed as follows:



Hint: You may find it easier to wire the male DSUB-9 connector if you first connect it to
the KPC-3 Plus and use the KPC-3 Plus as a “jig.” This may also keep the male pins
straight if you apply too much heat and soften the plastic in the male connector.

A shielded cable must be used with the shield properly terminated 360 to the
connector.

Instructions for making a cable assembly using the supplied foil shielded cable and
metalized plastic back shell follow:

1. Strip cable outer covering back enough to expose enough metalized plastic foil.
Do not cut or rip foil.

2. Carefully loosen the drain wire and foil from around the insulated wires.

3. You will need to build up the diameter of the cable, where it enters the back shell,
with any type of tape or sleeve, so that when the metalized plastic shell halves
are screwed together they will hold the cable as strain relief and press against
the metal foil.

4. Discard the metal strain relief pieces and screws that go with them—they are of
no use.

5. Connect wires as needed to terminals of connector. Keep track of which wire is
connected to which terminal.

6. Carefully fold the metalized foil back over the cable and Z-fold it so the metal side
of the foil is exposed to the connector back shell at the entrance area. Spread the
foil over the cable so you get as much coverage as possible (you will not get
360 coverage, but do the best you can).

7. Place the drain wire in the gap where you can not get foil coverage.

8. Place one of the shaped washers on each of the long, half-threaded screws, so
they are next to the head of the screw (with the bent ends of the washers facing
away from the heads of the screws).

9. Now place the metalized plastic shell halves together over the connector and
cable, with the (2) two long half-threaded screws and two shaped washers, to
attach the whole assembly to the KPC-3 Plus.

10. When you screw the two halves together there should be enough compression to
hold the cable in place and there should be solid contact between the metal side
of the foil and the metalized back shell. See figure below.

11. If your radio is equipped with a single metal connector, such as the Kantronics
dvr 2-2, then this same cable with connector attachment technique should be
used. Otherwise follow the wiring directions that follow.

50

Wiring between your Transceiver Microphone and the KPC-3 Plus:

Follow the notes taken above and wire the cable assembly in the following order:
Step 1. Using a user-supplied microphone connector appropriate for your transceiver

and the notes taken above, attach wires as follows:

 Attach the wire from pin 1 (transmit audio) on the DSUB-9 to the

microphone connector’s input pin,

 Attach the wire from pin 3 (push-to-talk) on the DSUB-9 to the

microphone connector’s PTT or STBY pin,

 (Optional) for base or mobile units, attach the wire from pin 9 (one path

to ground) on the DSUB-9 to the ground pin on the microphone
connector.

Connecting your Transceiver’s Speaker Plug to the KPC-3 Plus

Use an appropriate third party speaker plug and the notes taken earlier to do the
following wiring to the DSUB-9 cable assembly:

Step 1. Locate the wire that connects to the audio of the external speaker plug and

attach it to the wire from pin 5 on the DSUB-9 (Receive Audio)

Step 2. Locate the wire that connects to the ground of the external speaker jack and

attach it to the wire from pin 6 on the DSUB-9 (Ground)

This is all you need to do to wire the speaker plug part of the assembly.

51

Important: Keep your wiring notes for future reference.
This completes the construction of your transceiver cable assembly. Now it needs to be

connected.

Connecting the Transceiver Cable Assembly

Now you are ready to use this cable assembly to finish assembling your packet radio
station.

Step 1. Check to be sure all the parts of your completed cable assembly are properly

fastened and ready for connection to your transceiver and your KPC-3 Plus.
Step 2. Turn OFF all power.
Step 3. Plug the male DSUB-9 connector on the cable into the female DSUB-9

connector on the KPC-3 Plus’ “Radio” port,
Step 4. Secure the male DSUB-9 connector on the cable to the female DSUB-9

connector on the KPC-3 Plus’ “Radio” port, by screwing the two long, half-

threaded screws into the threaded nuts on each side of the KPC-3 Plus’

“Radio” port,
Step 5. Plug both the microphone connector and the external speaker jack into your

transceiver.

Adjusting the Receive Volume of Your Transceiver

To adjust the receive volume of your transceiver to the proper level (or to confirm that it
is already set at the proper level), do the following:

Step 1. Turn ON your computer (with your transceiver OFF),
Step 2. Start your terminal program,
Step 3. Turn ON your KPC-3 Plus,
Step 4. If not already done, set the KPC-3 Plus’ baud (ABAUD) and CALLSIGN,
Step 5. Turn ON your transceiver and open the squelch control (turn it fully counter-

clockwise),
Step 6. Slowly turn the transceiver’s receive volume up until the RCV LED (receive

indicator) on the KPC-3 Plus lights up (turns ON),
Step 7. Increase the transceiver’s receive volume control slightly above the point at

which the KPC-3 Plus’ RCV LED lit up (turned ON),
Step 8. Slowly turn the transceiver’s squelch control clockwise until the KPC-3 Plus’

RCV LED goes OUT (turns OFF),

52

Now the receive volume control on your transceiver is properly adjusted for sending
signals to your KPC-3 Plus.

Your KPC-3 Plus is now installed and ready to use. You may now go to the “Getting
Started” chapter, to learn how to do the basic operations with your KPC-3 Plus.



If you do not see the receive LED light, check the cabling between the radio and the
KPC-3 Plus. Also, until it has been initialized from the computer, the KPC-3 Plus will not
show ANY indication of receiving.



If you connected to a fixed level (unsquelched) receive audio from the radio, the receive
LED may remain on all of the time. In this case, set the parameter CD to SOFTWARE.
Then, the receive LED will not light until valid packets are heard. (see CD in the
commands section)

Transmit level adjustment

The 1200-baud data drive level (transmit audio voltage, TXA) from the KPC-3 Plus to
your radio is adjusted digitally, using your keyboard and the transmit level (XMITLVL) or
the calibrate (CAL) command. Previous models used a set of jumpers and an analog
potentiometer (pot) to set this level. With the KPC-3 Plus, no jumpers are used, just a
command.

You should adjust the drive level to provide about 3 to 3.5 kHz of deviation with your

radio. If you don’t have access to a deviation meter, adjust drive so your packet

transmissions generate about the same audio sound as packets heard from other
stations.

The XMITLVL command has a parameter default value of 100; this corresponds to a
drive voltage of about 50 mV. You may change this level by increasing the
parameter/count. For counts below 256, the voltage is increased in 0.5 mV steps; above
that, the drive increases roughly 15 mV per step.



For details, see the description of the XMITLVL command in the “Command
Reference.”

Alternatively, you may use the calibrate command (CAL) which has a zoom feature; that
is, you can hold down the ‘-’ or ‘+’ key to decrease or increase the voltage (as you watch
a meter or listen). See the commands section for more detail on these commands. CAL
is not available in the NEWUSER mode; you must be in TERMINAL mode to access
CAL.

The next section of this chapter is for those who wish to connect a GPS device to their
KPC-3 Plus. Skip this section if it does not apply to you.

53

Connecting to a GPS Device (Optional)

To use your KPC-3 Plus with a GPS device, you can connect the data output from the
GPS device to either the DSUB-25 “Computer" port (i.e., serial port) on the back of the
KPC-3 Plus or alternately, to a pin on its radio port.

Since you need to remove the computer’s serial modem cable from the KPC-3 Plus’

“Computer” port and replace it with the GPS’s cable before you can use the GPS device

with the KPC-3 Plus, you will need to use your computer to configure your KPC-3 Plus
to work with the GPS device before you connect your GPS device to your KPC-3 Plus.

Note: You can attach both the KPC-3 Plus and a GPS device to your computer at the
same time, using an APRS HSP (hardware single port) cable and the APRS program.

Since cabling may vary from one GPS vendor to another, the cable is not supplied with
your KPC-3 Plus. You will need to purchase or make a cable, using the specifications in
your GPS manual.

To connect the GPS receiver and the KPC-3 Plus as a “Stand-alone” position reporting
system without a computer, you will need to connect a minimum of 2 wires for data flow
from the GPS receiver to the KPC-3 Plus. Connect the GPS receiver “DATA OUTPUT”
to TXD (pin 2) on the KPC-3 Plus. Connect the GPS receiver “SIGNAL GROUND” to
signal ground (pin 7) on the KPC-3 Plus. Your GPS receiver may require other pins to
be connected, check its documentation.

An alternate input is available in the KPC-3 Plus (at firmware version 8.3 or later) for

GPS data, on its “Radio” port. The alternate GPS data input is enabled with the

command GPSPORT, and uses pin 2 on the KPC “Radio” port.

See your GPS manual and the chapter in this manual on “GPS NMEA Interfacing

Capability” for details on using your GPS device with your KPC-3 Plus based packet

radio station.



Note: some weather station devices have data outputs similar to GPS devices. The
configuration of the KPC, and connection to the device is the same.

This concludes the installation of your station.



For more information on installation topics, see the appendices.

54

Getting Started

This chapter gives you important information and examples to get you started using
your packet radio station.

We assume you have installed your station and familiarized yourself with the use of with
your KPC-3 Plus, as covered in the chapters on “Installing your KPC-3 Plus”.

If you have not yet installed your station, we suggest that you do so before continuing
with this chapter.

Material covered here includes diagrams, explanations, and mini-tutorials on:

 the front panel of the KPC-3 Plus,
 beginning a session,
 giving commands and transmitting data,
 the 22 NEWUSER commands that you will be using most of the time,
 using selected NEWUSER commands,
 using the Personal Bulletin Board System that is in your KPC-3 Plus,
 monitoring transmissions from nearby packet radio stations, and
 connecting to another station and initiating a conversation.



Reading this chapter (or just skimming the material, if you are already familiar with
the topics) will also help you use the following chapters on different modes of use of
the KPC-3 Plus, the “Command Reference” chapter, and any appendices that are
relevant to your needs.

55

The Front Panel of the KPC-3 Plus

You have already used the POWER switch on the KPC-3 Plus to turn power on and off.
This is a good time to get familiar with all the indicators on the front panel of the KPC-3
Plus.

The following diagram shows the placement and function of the controls and indicators
on the front of your KPC-3 Plus, as well as a brief explanation of each:

Beginning a Packet Session

The steps involved in starting a session are covered in detail in the “Installing your

KPC-3 Plus” chapter.
Start HyperTerminal, select the KPC-3 Plus icon, and turn on the KPC-3 Plus.
Once your initial setup is completed (including giving a CALLSIGN to your KPC-3 Plus

and setting other parameters as needed), the first thing you will see each time you start

Power switch

push in to turn power
ON, push in again to

turn power OFF

Power

Green LED is ON
when your TNC
is turned on and
receiving power

Transmit

Red LED is ON
when your TNC
is sending a
packet signal to

your transceiver

Receive

Green LED is ON
when your TNC
is receiving a
signal from your

transceiver

Connected

Green LED is ON
when your TNC has
a packet connection
on the current

stream

Status

Green LED is ON when
your TNC has at least
one unacknowledged
packet on the current
stream (i.e., a packet
that was transmitted to
another station has not
been acknowledged or
a packet is cued for
transmission

to another station)

Mail

Yellow LED is ON
when there is a
packet connection
to your TNC's
mailbox (i.e. , PBBS)
Yellow LED BLINKS
when there is
unread mail for you
in your PBBS and
there is currently no
packet connection
to your PBBS

56

a new session is a sign-on message from the KPC-3 Plus (sent to HyperTerminal and
displayed on your computer screen) such as the following:

KANTRONICS KPC3PMX VERSION 9.1
(C) COPYRIGHT 2002 -2005 BY KANTRONICS INC. ALL RIGHTS RESERVED.
DUPLICATION PROHIBITED WITHOUT PERMISSION OF KANTRONICS.
cmd:

The last line of this message (“cmd:”) is the KPC-3 Plus’ report that it is now in

“Command” mode, which means that it is now expecting information from

HyperTerminal to be commands for it (the KPC-3 Plus) to interpret and carry out. Before
learning about the specific commands you can give the KPC-3 Plus, it is important to
keep in mind the difference between giving the KPC-3 Plus commands and giving the
KPC-3 Plus data that is to be transmitted.

Giving Commands and Transmitting Data

The KPC-3 Plus will react to data received from HyperTerminal (or any other source)
either as a command to follow or as information to transmit.

Command Mode

When in the “COMMAND” mode of communication, the KPC-3 Plus will interpret data
received from HyperTerminal (or any other source) as being a command to process, not
as data to transmit. To instruct your KPC-3 Plus to connect, to disconnect, or to change
any of the operating parameters in the KPC-3 Plus you must be in the COMMAND
mode.



When placed in COMMAND mode (and ready to receive the next command) the
KPC-3 sends a “cmd:” prompt for display on the computer’s screen.

Converse (Conversation) Mode

When in “CONVERS” (conversation) mode, the KPC-3 will interpret data received from

HyperTerminal (or any other source) as data to transmit. In “CONVERS” mode, the

KPC-3 Plus interprets most characters as information to be transmitted, while
interpreting certain pre-defined characters (which the user can change) as control
characters rather than as data to be sent. For example, a “backspace” character causes
a backspace and is not transmitted.



The KPC-3 Plus will automatically switch to the CONVERS mode for you when you
connect to someone or when someone connects to you and will return to the
COMMAND mode when a disconnect occurs. When you are in COMMAND mode,
you may switch to CONVERS mode just by giving the command K (or CONVERS). If
you are in the CONVERS mode and want to force your KPC-3 Plus back to the
COMMAND mode, you type a <Ctrl+C>.

57

TRANS (Transparent) Mode

A second way to transmit data is to instruct the KPC-3 Plus to ignore the “control

characters” (e.g., “backspace”) and just transmit every character as data. This is called

the “TRANS” (transparent) mode of communication. For example, if data received by

the KPC-3 Plus for transmission in TRANS mode includes “backspace” characters (i.e.,
characters that would cause a backspace in CONVERS mode), the KPC-3 Plus will
transmit the backspace characters as part of the data.



Before you can switch to TRANS mode, you need to set INTFACE to TERMINAL
instead of NEWUSER. (This is because, as described in the next section, the
TRANS command is not a NEWUSER command.) To get out of TRANS mode and
back to COMMAND mode, enter “<Ctrl+C> three times, with a pause of less than
one second between each entry.

NEWUSER Commands

You have a choice of whether to have your KPC-3 Plus prepared to deal with a small
set of (22) NEWUSER commands (which is the default setting) or with the full set of
over 130 commands it is capable of carrying out.



Note: To switch to the full command set of the KPC-3 Plus, get in COMMAND Mode
(<Ctrl+C>) and give the command INTFACE TERMINAL. To switch back, give the
command INTFACE NEWUSER.

List of NEWUSER Commands

The following is an alphabetical listing of the 22 NEWUSER commands and a brief
description of each.

BKONDEL - When ON echoes a backspace-space-backspace sequence to the screen
each time you press the DELETE key to erase errors from your screen. When OFF,
echoes a \ for each press of the DELETE key.

CONNECT - Used to establish a packet connection with another station.
CONVERS - Places the KPC-3 Plus in CONVERS mode.
DISCONNE - Used to disconnect from a station you have been talking to.
DAYTIME - Used to read or set the clock in the KPC-3 Plus.
DELETE - Determines the character received from the computer which will cause the

previous character to be removed from the transmit buffer.

DISPLAY - Causes a screen display of all KPC-3 Plus parameters.
DWAIT - Time delay imposed to insure that digipeaters have priority access to the radio

frequency.

58

ECHO - When ON characters you type on the keyboard will be echoed back to your
terminal. When OFF characters you type will not be echoed.

HELP - Displays a complete list of all available commands on your screen.
INTFACE - Selects the NEWUSER command set or the complete (TERMINAL)

command set. Also used to place the KPC-3 Plus in HOST, BBS, KISS, XKISS,
MODEM or GPS mode.

K - Switches the KPC-3 Plus into the CONVERS mode (same as CONVERS).
MONITOR - When ON allows the KPC-3 Plus to display monitored packets on the

screen. When OFF, no packets will be displayed unless someone actually connects to
you.

Select the current interface mode

INTFACE: Set the current interface mode to NEWUSER, TERMINAL, BBS, HOST, KISS, XKISS, GPS or

MODEM. Default is NEWUSER, which makes available just the basic commands listed here.

Get help and other information about your KPC-3 Plus

HELP: List all available commands or a brief description of a specified command.
DISPLAY: Show current values for all parameters or for a specified group of parameters.

VERSION: Show the version number of the EPROM (firmware) installed in your KPC-3 Plus.

Configure your KPC-3 Plus

RESET: Restart the modem -- equivalent

to turning your KPC-3 Plus
OFF, then ON again ("soft reset").

MYCALL: Change your KPC-3 Plus’ callsign.
DAYTIME: Set your KPC-3 Plus’ software (and optional hardware) clock.
TXDELAY: Set the transmitter key-up delay (default is 300 ms).
DWAIT: Time delay imposed to insure that digipeaters have priority access to the radio frequency.

Display communication activity

MONITOR: Display packets from other stations (default is ON).
STATUS: Display current I/O stream and link status of other connected streams.

MHEARD: Display a list of stations recently heard by your KPC-3 Plus.

Define your KPC-3 Plus’ use of characters sent to it from your computer

ECHO: Display characters you type (default is ON, for use with full duplex communication programs).
BKONDEL: Select the effect of entering a "delete" (i.e., erase the previous character or display a "\").

DELETE: Change which key your KPC-3 Plus will interpret as "delete" (default is backspace key).

Configure your personal mailbox (PBBS)

MYPBBS: Change the callsign of your PBBS.

PBBS: Change the size of your PBBS (i.e., RAM used).

Session control

CONNECT: Start a session (i.e., connect to a station) and automatically switch to CONVERS Mode.
DISCONNE: End a session (i.e., disconnect from a station).

UNPROTO: Set a destination and digipeater path for unproto packet transmissions.

Switch from giving your KPC-3 Plus commands to using it to send data

CONVERS: Switch from COMMAND communication mode to CONVERS (i.e., conversation)

Mode. The default way to go back to COMMAND Mode is to enter <Ctrl+C>.

K: Same as CONVERS.

NEWUSER Commands

NEWUSER commands are a subset of the full TERMINAL command set. NEWUSER commands are all

you need for basic, beginner operations of your packet radio station. These commands

are explained in the Command Reference section of the manual.

59

MHEARD - Displays a short list of stations that have recently been heard by your
KPC-3 Plus.

MYCALL - Used to set the callsign of your KPC-3 Plus.
MYPBBS - Sets the callsign used for your personal mailbox in the KPC-3 Plus.
PBBS - Used to set the size (kbytes) of the Personal BBS in your KPC-3 Plus.
RESET - Causes the KPC-3 Plus to perform a soft reset.
STATUS - Displays the status of the current stream and all connected streams.
TXDELAY - Sets the time delay between Push-to-Talk and the beginning of data.
UNPROTO - Sets the destination field and digipeaters used for any unconnected data

packets transmitted.
VERSION - Displays the current version number of the EPROM (firmware) in your

KPC-3 Plus.

Using NEWUSER Commands

A brief look at the use of selected NEWUSER commands will give you the familiarity
you need to continue on your own using KPC-3 Plus commands.

Check Your KPC-3 Plus’ Version Number and ID

To check your KPC-3 Plus’ version number and ID all you need to do is ask to see the
current setting of the command called VERSION:

Step 1. Go to COMMAND mode (if you are not already there).
Step 2. Type “VERSION” (or the short form, “V”) and press the ENTER key to enter

the command.
Step 3. The KPC-3 Plus will send its version number and other ID information for

display on your monitor.

Get Help

To see a one-line explanation of any command that is currently available:
Step 1. Go to COMMAND mode (if you are not already there).
Step 2. Type “HELP,” (or “?”) followed by one or more spaces and the name of the

command for which you want help.
Step 3. The KPC-3 Plus will send a short “HELP” message about the command, for

display on your monitor.

60

View Current Values of Parameters

To see the current value of parameter(s) for any variable (other than the “immediate”
commands, like CONVERS, that are simple actions, not settings):

Step 1. Go to COMMAND mode, as described above (if you are not already there).
Step 2. Type the name of the command for which you want to see current parameter

value(s).
Step 3. The KPC-3 Plus will send a message consisting of the name of the command

and the value(s) of its parameters for display on your monitor. For example, if

you type INTFACE, you will see INTFACE NEWUSER if you are currently in

the NEWUSER mode.

As explained in the “Command Reference” chapter, the DISPLAY command can be

used to see current values of selected sub-sets of commands.

Change the Value of a Parameter

To change the current value of parameter(s) for any variable (other than the
“immediate” commands, like CONVERS, that are simple actions, not settings):

Step 1. Go to COMMAND mode, as described above (if you are not already there).
Step 2. Type the name of the command for which you want to change the current

parameter value(s), type one or more spaces, and enter the new value(s) you

want for the parameter(s) for the command.
Step 3. The KPC-3 Plus will immediately change the value(s) to the values(s) you

have just entered.
If you enter a value that is not possible (e.g., INTFACE MOON), you will get an error

message (“EH?”).
To confirm that the current value(s) is what you want, enter the name of the command

and press ENTER. The KPC-3 Plus will send a message consisting of the name of the
command and the current value(s) of its parameter(s) for display on your monitor.

Connect to Your Mailbox

You are now ready to try your first connect.
A good first connect (which also shows you an important part of your KPC-3 Plus), is to

simply connect to your own personal mailbox, built in to the KPC-3 Plus:



This is an internal connect, so your radio does not need to be connected.

Step 1. Go to COMMAND mode (if you are not already there), where you will see the

“cmd:” prompt.

61

Step 2. Type CONNECT call (where “call” is your MYPBBS) and press the ENTER

(return) key to enter the command. By default, MYPBBS is the callsign you

entered right after the autobaud routine, with “-1" appended to it.

Note: To see the current mailbox callsign, type MYPBBS and press the

ENTER (return) key. The callsign shown is the one to use when connecting to

your mailbox (PBBS)
Step 3. Your KPC-3 Plus will connect you to the mailbox. Your screen should look

something like this:

cmd: CONNECT NØKN-1
cmd:*** CONNECTED to NØKN-1
[KPC3P-9.1-HM$]
47500 BYTES AVAILABLE IN 15 BLOCK(S)
ENTER COMMAND: B,J,K,L,R,S, or Help>



The commands now shown as available are just for the mailbox. The KPC-3 Plus’
NEWUSER (and TERMINAL) commands become available again when you exit the
mailbox.

Step 4. Now you can give any of the mailbox commands shown (B,J,K,L,R,S, or

Help). Later you will want to read the “PBBS (Personal Mailbox) section of the

“Modes of Operation” chapter for more details. If you now type the HELP

command and press return, you’ll see the KPC-3 Plus mailbox help file and

then the standard mailbox prompt:

ENTER COMMAND: B,J,K,L,R,S, or Help> .

Step 5. Now disconnect (just like you will disconnect from any other user).

First, return to command mode by typing a <Ctrl+C> on your keyboard. To do

this, hold down the control key (usually marked Ctrl) and type the letter C.

Then let go of the control key.

You should now see the “cmd:” prompt.

Next type the DISCONNE command and press return.

You will receive the message *** DISCONNECTED and a new command

prompt.
Congratulations. You have now completed your first connect.

Monitor Communications From Nearby Stations

A good way to start using your packet radio station is to monitor communications from
nearby stations.

62



Amateur packet-radio activity in the US is typically on VHF, on 2 meters, with

145.010 MHz being the most common packet-radio frequency. The most common
baud is 1200.

To monitor communications from nearby stations (after you have tuned in to an
appropriate frequency):

Step 1. Set MONITOR to ON (if it is not already ON).
Step 2. Disconnect from any other station (or mailbox).
Step 3. As packets are received, you will see them displayed on your screen. A

typical received packet might look like this:

NØKN>KBØNYK:
Hi Mike. How are you today?

The first line is the header line, and shows the callsigns of the stations talking

and the following line(s) are the actual message that was sent. In the

example, NØKN is the transmitting station, and KBØNYK is the receiving

station. You may see the RCV LED light at times, indicating a signal is being

received, but nothing displays on your screen. This is normal and may be the

result of the settings of the monitoring commands, which are discussed in

detail in the KPC-3 Plus Command Reference.
As you monitor, you will begin to learn about other packet stations in your area and then

you will probably want to try to connect to one of them.

Communicate Directly with a Nearby Station

Now you are ready to carry on a two-way conversation with another station. Here we
will see exactly what you need to do to connect to and converse with another station.

Let’s say that you decide to connect to KBØNYK. The steps needed are as follows:
Step 1. First, be sure you have the KPC-3 Plus in command mode. To do this, type

<Ctrl+C> and then press return. You should see a command prompt (cmd:).
Step 2. Now you use the CONNECT command. To connect to KBØNYK, you would

simply type CONNECT KBØNYK and press return, just as you did in the

sample connect to your mailbox.



In some cases you may need to use a relay station (called a digipeater) to contact
another station. This is similar to using a voice repeater when the station you want to
talk to is out of simplex range. To connect to a station using digipeaters, you still use
the CONNECT command, but you must also specify the callsigns (or aliases) of the
digipeaters that must be used. For instance, if you need to use two digipeaters with
callsigns of WØXI and NØGRG in order to connect to KBØNYK, you would give the
connect command as “CONNECT KBØNYK VIA WØXI,NØGRG”

63

Step 3. Once the connection has been made, you’ll receive a message back on your

screen from the KPC-3 Plus that says *** CONNECTED to KBØNYK (or, if

you are using relay stations, *** CONNECTED to KBØNYK via WØXI,

NØGRG). At that point you are ready to start talking to the other station since

the KPC-3 Plus has already automatically switched into the CONVERS mode.
Step 4. After you have completed your conversation, simply press <Ctrl+C> to return

your KPC-3 Plus to the command mode (“cmd:” will be displayed) and then

you can instruct your KPC-3 Plus to disconnect as you did above with the

mailbox, by entering D (or the full form, DISCONNE) and return.
As you begin working with your KPC-3 Plus packet radio station, other topics that you

may wish to explore (with the help of other sections of this manual) include:

 doing hard and soft resets,
 communicating via relays with a distant station,
 using network nodes, and
 working with a GPS device.

This concludes a quick tour of basic uses of your KPC-3 Plus. With just these basics,
you can do a lot, but you have a great deal more power if you want to explore the full
possibilities.

For more information on all the topics we have covered here, and more, see the
following chapters in this manual.

64

Modes of Operation

This chapter covers the major ways in which you may use your Kantronics TNC. For
details on particular commands, see the “Command Reference” chapter.

Packet Mode of Operation

This section adds to the information presented earlier (in the Getting Started and other
sections) on how packet radio uses digital information for communication. By
familiarizing yourself with the concepts presented here, you’ll be aware of and, if you
wish, able to change the default value(s) of the command parameters in your TNC to
optimize your packet activities.

Introduction

Information is Organized into “Packets”

A packet is a group of characters with a flag and header at the beginning and a
checksum and flag at the end. A flag is a specific character used to signify the
beginning and ending of a packet. The header is information indicating who the packet
is from, who it is to, any relay stations needed to get to the destination and some control
information. A checksum is a complicated mathematical formula that produces a
number based on the combination of characters that are in the packet. This number is
recalculated by every station that receives the packet, and if it does not match the
number that is in the packet, the packet is thrown away, thus near error-free
communications. A packet is also called a frame.

Your Packet Unit is a Terminal Node Controller (TNC)

Packet radio modems, or packet modems, are generally referred to as TNCs. This

“label” or “moniker” was adopted when the Tucson Area Packet Radio Group (TAPR)

developed their first “TNC-1" packet radio modem kit in the early 1980s. The TNC is the

workhorse of packet radio. As a listening device it hears an audio signal from the radio,
changes the data to digital form, determines if the data is a good packet and sends it to
whatever device is attached, usually a computer. As a relay device it also checks the
packets it receives and determines if the packets need to be resent, then does so if
appropriate. As a sending device it receives digital data from the computer, packetizes it
and changes it into audio tones, which are sent out to the radio. The rule the TNC uses
to do all of this is called a protocol.

Protocol for Amateur Packet Radio: AX.25

The most commonly used protocol in amateur packet radio is AX.25. The details of the

inner workings can be found in a book titled “AX.25 Amateur Packet-Radio Link-Layer
Protocol”, which is available from the ARRL. Most TNC users will not need to or care to

go into the details. The TNC takes care of the nitty gritty work for you, although there
are parameters you can set that determine how efficiently some of that work is done.

65

Command Mode

In order to change parameters, or give any other instructions to the TNC, you must be in
Command Mode. This is the mode you will be in when you first turn on the TNC or after
resetting it.

Once you have left Command Mode for any reason, there is a parameter called
COMMAND that determines what special character you will use to return to Command
Mode. This comes defaulted as a <Ctrl+C> (i.e., while holding down the control key,
press “C”, then release both keys).

Whenever you enter Command Mode the TNC will send a prompt to your screen that
looks like this:

cmd:

Connected vs. Unproto

There are two ways to send data in packet radio, connected or unproto (unconnected).
In the Connected Mode you first establish a connection. Then your TNC will send
packets to that specific station and expects acknowledgments in return. If an
acknowledgment is not received, the TNC will resend the data (depending on the setting
of AX25L2V2, it may send a poll first). The RETRY parameter will determine how many
times this is done before the connection is lost due to bad conditions. If the
acknowledgment is received, the TNC is happy and will send more data when available.
Therefore the Connected Mode, barring impossible conditions, assures that the station
you are connected to will receive everything you say, and in the order you say it.

In the Unproto Mode, when your TNC sends a packet, no acknowledgment is expected
and no retries are attempted. This mode is often used for calling CQ, for transmitting
beacons, and for informal round table chats.

Monitoring and Calling CQ

If you turn the MONITOR command ON, you will see other people’s packets on your
screen. You will notice two callsigns at the beginning of each packet separated by a “>”.

The first callsign is the station the packet is from, and the second callsign is the station
the packet is to. An Unproto packet may have a name or CQ for the second callsign.

To set what will be seen as the “to” callsign for Unproto packets you send, you use the

UNPROTO command. This comes defaulted as CQ.
In order to call CQ you must get into the Convers Mode, so that what you are typing to

the TNC will be interpreted as data to be sent out on the air and not as commands. To
do this type:

K<CR>

Now anything you type will be packetized and sent out on the air. Remember to get
back to Command Mode you enter a <Ctrl+C> (default) by holding down the Control key

66

while pressing “C”. You will be going between Command and Convers Modes

depending on whether you want to talk to the TNC or have the TNC packetize what you
type to go out on the air.

A Simple Connect

Once you see a station you would like to connect to, be sure you are in Command
Mode, and issue a connect request. For example:

C callsign<CR>

where ‘C’ is short for CONNECT and ‘callsign’ is the callsign of the station you wish to
connect to.

If for any reason the connection fails, the TNC will send the following message to your
screen:

*** RETRY COUNT EXCEEDED
*** DISCONNECTED

When your TNC does receive an acknowledgment for a connect packet, it will display a
message on your screen like:

*** CONNECTED TO callsign

Then your TNC will change to the Convers Mode (dependent on the setting of
NOMODE and CONMODE). Now what you type will be interpreted by the TNC as data
to be sent to the other station and not commands to the TNC. The MCON parameter
comes defaulted to OFF. Therefore once you are connected all you will see is what you
type and what the person connected to you sends you. Any packets sent by other
people will not be monitored unless they are also connected to you on another stream.

Two things determine when the data you send will be packetized. One is the parameter
SENDPAC. This is defaulted as the return or ENTER key. So as you are typing your
message, whenever you hit the return or ENTER key, you are telling the TNC to make a
new packet. A second parameter, PACLEN, determines the maximum length of any
packet. If you enter data longer than this length, a packet will be made even though you
have not pressed the return or ENTER key.

When you have finished your conversation you need to end the connection. To do this

you go into the Command Mode and type a “d” for Disconnect. Remember to press the

return or enter key after any command to the TNC. Once your station has received the
acknowledgment for the disconnect packet the TNC will send this message to your
screen:

*** DISCONNECTED

Either station can issue the disconnect command, no matter which station originated the
connect.

67

Digipeating

Everything we have done so far will only be heard by those within range to hear your
signal. With packet radio it is possible to go farther than that. The DIGIPEAT parameter
in the TNC comes defaulted ON. This makes your TNC a possible relay station, or
digital repeater —digipeater, or just digi for short. In many VHF communities one or
more of these is put up in a good, high location and referred to as a dedicated digi. The
TNC and radio is all that is needed for the digital repeater to do its job. A computer
would be needed if you wanted to change a parameter, but it would not need to stay
there for the digi to work. The higher the antenna, the more effective a digi will be, but
remember, every TNC has the capability of being a digipeater.

If we turn the MRPT command ON we will begin to see more than just the “from” and

“to” stations of the monitored packets. We will also see the callsigns of those stations

that have been used as digipeaters. This list of stations is often called a path. Here is an
example of what you might see:

NØKN>KBØNYK, IAH*,LAG,AUS:
Hi there

In this example, NØKN is talking to KBØNYK, using the digipeaters IAH, LAG and AUS.
The asterisk beside IAH tells you that you are hearing that digipeater. You will notice
that IAH, LAG and AUS are not real callsigns. The TNC provides a parameter
(MYALIAS) to set up an alias, which is often easier to remember than a callsign. To
make this connection NØKN would have typed the following command to his TNC:

C KBØNYK V IAH,LAG,AUS

V is short for via and up to 8 digis may be used. You must specify digis in the order they
will be encountered along the path from your station to the station you wish to connect

to. A space must be typed after the “C” and on both sides of the “V”, but digis are

separated by commas. A path can also be used with the Unproto command:

U CQ V NOM,LCH,SLI,BIX

Unproto sets up the path for anything that is subsequently typed in the Convers Mode
where no connection exists. CONNECT issues a connect request to the specified
station, via the specified path. Then a virtually error-free conversation can take place
between them.

When digipeating, the packet goes all the way from the first station, through all relay
stations, to the destination station. Then the response also has to take this same path in
reverse. Chances for collisions and, therefore, for retries are multiplied with every digi
used. This is often called end-to-end acknowledgment. Another way to get from one

place to another is to connect to a “node”. A node will take care of the acknowledgment

between it and the next node or end user. See the KA-Node section for more
information. Ask your local packeteers about other types of nodes which may be
operational in your area, such as K-Net, TheNet, NET/ROM, G8BPQ, and ROSE.

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

Kantronics’ TNCs support additional, advanced UI digipeating commands. For a

description of Kantronics’ UI digipeating commands, see “Advanced GPS (or APRS)
digipeating”, in the GPS Mode of Operation section of this chapter.

Gateways

In Kantronics’ multi-port devices (e.g., Kantronics’ KAM Plus, KAM XL, and KPC-9612
Plus), a Gateway is also available.

Using a gateway is similar to digipeating except that the retransmission of the packet
takes place on another radio port of the TNC other than where it was received. In other
words, if you are on VHF and send a packet via a Gateway callsign of a KAM, your
packet would be retransmitted on HF on whatever frequency the radio connected to the
KAM is set for. When you use one of these gateways on HF, remember that on HF the
baud is slower so you may want to lengthen some of your timing parameters. See the
KA-Node section for another way to accomplish this with a more reliable connection.

Multi-Connects

The TNC makes it possible for you to talk to more than one person at the same time.
Single port TNCs such as the KPC-3 Plus support 26 streams on the one port.



Multi-port TNCs (e.g., KPC-9612 Plus) support 26 streams per port.

The command MAXUSERS determines how many streams may be used at one time,
per port, and the command USERS determines how many people can connect to the
TNC per port. An incoming connect uses the next available stream. If the number of
streams set by USERS is full, then a station attempting a connect with your TNC will
receive a busy message instead of a connect. However, if MAXUSERS is set larger
than USERS, you can still issue outgoing connects on additional streams.

To determine which port you are on, simply use the STATUS command, typing STAT at
the command prompt. The TNC will report which streams are active and which one you
are on. If you wish to remain on the current stream to communicate, no action is
necessary. To change streams ( to make another connect or to send data to another
station already connected to you) type the STREAMSW character, the number of the
port (if you are changing ports on a multi-port TNC), and the letter designation of the
stream you wish to be on. No return or enter key is necessary.

For example, let’s assume you are using a KPC-9612 Plus and you are connected to
WØXI on stream A of port 2 but you wish to return to a discussion with NØGRG on
stream B of port 1. Whether in command mode or convers mode, simply enter “|1b” and
the TNC will switch to port 1, stream B. When you do this, the CON and STA lights on
the front panel will switch with you, reporting the status of the new stream.

If you are connected and have MONITOR or MCON OFF, the normal headers

containing the “to” and “from” callsigns will not be shown. The setting of STREAMEV will

then determine how often you see the stream designator. This parameter comes
defaulted OFF, so the stream designators are only shown when a change in streams

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occurs. Turning this command ON will make the stream designators show on every
connected packet received. Turning STREAMCA ON will also add the callsign of the
“from” station beside the stream designator.

Round Table Discussions

Several people talking together present a difficult situation for packet radio since the
protocol requires two stations to connect in order to make sure they receive each
other’s packets. If you wanted to be absolutely sure that everyone got everything you
said, you would have to connect to each person and retype everything to each person.
That could get a bit cumbersome, so most people use the Unproto Mode and are aware
that a collision may occur once in a while. You can usually tell by the conversation if

something was missed; if you don’t get an answer to a question it’s probably not that he

is ignoring you, but either the question or the answer was corrupted by a collision.

Selective Monitoring

With MONITOR ON, the BUDLIST command can help in setting up your monitoring so
you will see only those packets you want to see. You can list up to 10 calls in BUDLIST.

Timing

Dwait vs. Persistence and Slottime

When the TNC acts as a digipeater, packets received that need to be relayed are
retransmitted as soon as the frequency is clear. Other TNCs on frequency (should) hold
off or wait their turn, using a PERSISTENCE/SLOTTIME algorithm or DWAIT method to
determine when to transmit. This practice has been adopted to reduce collisions with
packets being digipeated, since these packets must (by the AX.25 protocol) be
acknowledged end-to-end. Kantronics’ current TNCs (e.g. KPC-3, KPC-3 Plus,
KPC-9612, KPC-9612 Plus, among others), use the PERSIST/SLOTTIME algorithm to
gain channel access. The default value for DWAIT is set to zero. If the DWAIT method
is used, the TNC sending non-digipeat packets will wait for DWAIT (times 10
milliseconds) time of clear channel before beginning to key-up the radio to transmit.

The algorithm used with the PERSIST and SLOTTIME parameters helps avoid
collisions by randomizing the wait time before transmitting. The more random the timing
the less chance of two TNCs transmitting at the same time and colliding.

Once the TNC detects a clear frequency it will wait SLOTTIME (times 10 milliseconds).
Then, if the channel is still clear, it will generate a random number. If this number is
smaller than the setting of PERSIST the TNC will transmit. If it is larger it will wait
another SLOTTIME and then generate another random number and again decide
whether to transmit or not. When using PERSIST and SLOTTIME you should set
DWAIT to 0, since both will be used if specified.

As an example, let’s assume that PERSIST is set to 63, and SLOTTIME is set to 10.

This value of SLOTTIME results in a random number being generated every 100
milliseconds. When the TNC sees that the channel is clear, it waits 100 ms, then
generates a random number between 0 and 255 (inclusive). If, in our example, the

70

number was 83, then the TNC would not start the key-up of the transmitter since 83 is
greater than the 63 PERSIST value. Instead, it would wait an additional 100 ms, and if

the channel is still clear, generate a new random number. This time, let’s say it comes

up with the number 27. Since this is less than the PERSIST value, we now start the key­up of the transmitter to send the packet.

Txdelay

TXDELAY should be adjusted to allow your radio sufficient time to switch from receive
mode to transmit mode and develop full power output. If the TNC sends the packet
before the radio is at full power, the beginning of the packet will be lost and no one will
be able to decode it. TXDELAY also allows the station you are talking to sufficient time
to switch from transmit mode back to receive mode. The TNC sends flags during the
TXDELAY period, so if someone has this set extra long you will hear a repetitive sound
at the beginning of the packet.

Frack (Frame Acknowledgment Time)

If the TNC expects an acknowledgment of a packet it has sent, it will wait FRACK
seconds for the acknowledgment. If the acknowledgment is not received it will either
send a poll or retransmit the packet, depending on the setting of AX25L2V2. When digis
are used, extra time is allowed for each transmission using the following equation:

FRACK * ((2 * n) + 1) seconds

where n is the number of digipeaters. The lower the baud (HBAUD) the higher this
parameter should be set, because everything is slower. The length of the transmission
(determined by PACLEN and MAXFRAME) also needs to be taken into account when
deciding how to set FRACK. Longer packets (and more of them) require more time to
be transmitted, more time to be repeated by the digipeater, and so on down the line.
The FRACK timer begins when PTT is released (the packet has been sent) and is
suspended when data carrier from the radio is present, or when your station is
transmitting.

Retries AX.25 Level 2, Version 1 vs. Version 2

The way retries are accomplished depends on AX25L2V2 being OFF or ON. To explain
this we will follow a conversation through its path. First let’s assume station “A” is

connected to station “B” with Version 1 protocol (AX25L2V2 OFF). When station A

sends a packet to station B, he expects to receive an acknowledgment back indicating
that station B has received the information. In order to verify that the proper packet (or
frame) has been acknowledged each frame has a number. This number is sent as a
part of the frame so the receiving station knows where this packet belongs in the
conversation. The frame numbers range from 0-7 and because of this, we are limited to
a MAXFRAME of 7 (we do not want the same frame number reused in the same
transmission). This is also true for Version 2. If the first acknowledgment is received,
there is really no difference between the two versions, practically speaking. The

difference shows up with retries, so let’s assume that the packet did not get through on

the first attempt.

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Let’s assume that station A sends frame number 3 to station B. Station B does not

receive the frame and therefore no acknowledgment is received by station A. With
version 1, the entire packet is retransmitted (with the same frame number) to station B
and this continues until station A receives an acknowledgment from station B. This
acknowledgment can take two basic forms. The first time station B receives frame 3 he

will send an acknowledgment of the form “ready to receive frame 4” <rr4>. If this

acknowledgment is sent, and station A did not receive it, station A will again send frame

3. Since station B already received frame 3, he would acknowledge it with the form “I’ve

already got that frame, send me number 4” <rej4>. This is also known as Reject Frame

sent. This process would continue until the retry count is exceeded when, under version
1, the sending TNC will initiate a disconnect and discard the packet. (The monitoring of
the commands shown in < > depends on the settings of MRESP, MCON and MCOM.)

Now let’s look at the same conditions under version 2 (AX25L2V2 ON). Station B does

not receive frame number 3 from A and therefore sends no acknowledgment to station

A. This time, station A sends a POLL or question to station B saying, in effect, I’m

expecting frame number 0 from you; what frame are you expecting from me?"
<<RR0>>. Since station B did not receive the frame, station B would respond with

<<rr3>>, saying “I’m ready to receive frame 3.” At this point, station A, upon receiving

the rr3 would immediately resend the entire frame. If station B had already received
frame 3 once but the acknowledgment never got to station A the question from station A

for the retry would be the same. Station B’s response however, would be different. He
would respond with “ready to receive frame 4” <<rr4>>. If station A does not receive

station B’s reply, this “POLL/REPLY” sequence would continue for the number of retries

set in the sending TNC; if no response was received, and the RELINK parameter is ON,
the TNC at station A would then begin to issue connect requests to station B since there
is still an outstanding packet of information. This is the major difference between version
1 and version 2. The connect attempts would then continue for the number of retries set
in the TNC, and if no response was received from station B after all of the above, station
A would disconnect and discard the packet. The parameter RELINK is defaulted OFF to
avoid the reconnect attempt.

Flow Control

The flow control commands insure that the TNC gets everything that is sent to it by the
computer and that the computer gets everything the TNC sends it. When the computer
sends the TNC data, the TNC stores this data in a buffer until it can packetize it, send it,
and get acknowledgments. Similarly, when the TNC sends the computer data, the
computer stores the data in a buffer until it can be processed, stored to disk, sent to
printer, or whatever.

This buffer area is of limited size; if more data is sent than will fit in the buffer the extra
data will be lost. To make sure each device gets all the data it should from the other
device, the two devices can tell each other to start and stop sending data. This is called
Flow Control and it can be accomplished in either of two ways, via software or via
hardware.

Which way you implement this depends on the capabilities of your computer
communications program and personal preference. The cable between your computer
and TNC must also be wired appropriately.

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Software Flow Control

Software flow control sends special characters on the TXD and RXD lines of the RS232
cable. These are the same lines used for sending regular data between the TNC and
computer. Software flow control normally sends a <Ctrl+S> to stop data and a <Ctrl+Q>
to restart data. When a buffer gets close to full, the device will send a <Ctrl+S> and
expect the other device to stop. When the buffer gets nearly empty, it will send a
<Ctrl+Q> to tell the other device to send more data. How full or empty a buffer is when
the special characters are sent is determined by the program. But, since the regular
data lines are being used, a <Ctrl+S> sent as data from the keyboard will also stop data
from the TNC. And likewise, if there is a <Ctrl+S> in a file being sent, data flow from the
TNC will stop until a <Ctrl+Q> is received.

XFLOW needs to be turned ON for the TNC to use software flow control. XOFF
determines the character sent by the TNC to stop the flow of data from the computer,
and the XON character restarts the flow. The TNC expects the computer to send the
STOP character to stop data to the computer and the START character to restart data.
To use software flow control these commands would be set as follows: XFLOW ON,
XOFF $13, XON $11, STOP $13, START $11. (Default settings.)

Two commands are provided to make it possible to send and/or receive these special
characters in Transparent Mode and still use software flow control. TXFLOW enables
flow control sent by the TNC to the computer and TRFLOW enables the TNC to
recognize flow control sent by the computer. If both these commands are ON (and the
above commands are set as stated) then software flow control will take place in both
directions, to and from the TNC and computer.



If you are in Transparent Mode sending a file, the computer does not need to tell the
TNC to stop and start (since you are sending the file). By turning TRFLOW OFF and
TXFLOW ON, the TNC will accept START and STOP characters embedded in the
file and send them along to the radio as data. Meanwhile, the TNC can send the
XOFF and XON characters to the computer to control the flow of data from the
computer. When receiving a file, turn TRFLOW ON and TXFLOW OFF; the
computer will accept all data and use START and STOP characters to control the
flow of data from the TNC.

Hardware Flow Control

Hardware flow control monitors the voltages on the RTS and CTS pins of the RS232
cable. Therefore these two pins must be wired between your TNC and a connected
computer. The TNC holds CTS high as long as it can receive data. Once its buffer gets
full, it pulls this line low. The computer program monitors this line. When it is pulled low,
it knows to stop sending data. When the line is again pulled high by the TNC, the
computer program will restart sending data. On the other hand the computer holds RTS
high as long as it can receive data and pulls it low to tell the TNC to stop sending data.
The TNC always uses hardware flow control, so only wire the RTS and CTS pins if your
computer program is also using hardware flow control.

73



HyperTerminal uses hardware flow control, but some communication software does
not.

Convers Mode vs. Transparent Mode

In the Convers Mode there are many special characters. To list a few:

Command Default Description

SENDPAC <Ctrl+M> Causes a packet to be formed
DELETE <Ctrl+H> Backspace character
REDISPLAY <Ctrl+R> Redisplays the keyboard buffer
CANLINE <Ctrl+X> Cancels a line
STOP <Ctrl+S> Stops output from TNC to computer
PASS <Ctrl+V> Pass a special character

These characters are all very useful when having a packet conversation with someone.
If you want to send a packet you hit the return. If you make a mistake you can erase
characters, using the delete or backspace key, or kill the whole line with <Ctrl+X>. And
if you really want to transmit one of these characters, you can always precede it with a
PASS character.

Transparent Mode was designed for the sending of files, whether they be ASCII data
files or program files. Special characters have no meaning to the TNC in transparent
mode, they are just characters to be put in a packet and sent to the radio.

In Transparent Mode, a SENDPAC character will not cause data to be formed into
packets; instead, packets are formed at a rate that is set by PACTIME.

All monitor commands are treated as OFF in Transparent Mode. All you will see is what
is being sent to you. You would probably want to set USERS to 1 so no one interferes
with the transfer. The setting of ECHO is also ignored. Even if ECHO is ON Transparent
Mode will not echo to the attached terminal. Some programs allow for local echoing to
the screen while uploading.

Getting Out of Transparent

Getting into the Transparent Mode is easy: you just type a “t” in Command Mode. But
since Transparent Mode allows the sending of all characters you can not get out of
Transparent Mode by just typing a <Ctrl+C> (COMMAND character) as in Convers
Mode. In order to get out of Transparent Mode, you must follow a special sequence, or
use a modem break if your program supports one. The special sequence must be
followed precisely. This example assumes the COMMAND character is <Ctrl+C> and
CMDTIME is 1 second:

 Wait at least 1 second since the last character was sent from the computer to the

TNC

 Type a <Ctrl+C>

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 Within 1 second type a second <Ctrl+C>
 Within 1 second type a third <Ctrl+C>
 Wait 1 second and the cmd: prompt should appear

If the guard time of one second before and after the three <Ctrl+C>s is not there, the
TNC assumes that they are data and sends them to the radio, so be sure to allow at
least one second before and after the three <Ctrl+C>s.

Remote Access to Your TNC

You can connect to your TNC from a remote station and change values of your TNC’s

parameters. This allows you to add or delete stations from the LLIST, change the size of
the PBBS, change the MYCALL and so on, all remotely. Extreme caution must be used
when you are accessing your TNC from a remote location. There is no built-in
safeguard, and as such it is possible for you to change parameters such that the remote
TNC will no longer communicate with you.

In order to change parameters in a remote TNC, the RTEXT in the remote TNC must be
set to a text string that will be used as the password string. For instance, you might set
your RTEXT to:

RTEXT Code

The remote TNC must also have its MYREMOTE set to a unique callsign (i.e. WØABC­4, or XYZREM). If these two parameters are not set, remote access to the command set
of this TNC is not possible. When these parameters are set, you can connect to the
MYREMOTE callsign of the remote TNC.

When the connection is made, the remote TNC will send three lines of numbers. The
numbers may look like:

1 1 1 3 4 3
3 1 4 3 1 3
2 1 1 2 1 3

You must then pick ONE of these lines and decode the password string. Let’s say you
choose to decode line 3 (2 1 1 2 1 3). Rewriting your RTEXT string to make this easier
you would have:

Character #: 1 2 3 4
Letter: C o d e

Therefore, to gain remote access, you must send the following string:

oCCoCd

(since small letter o is at position 2, capital C is at position 1, and so on)
Note that case is significant and spaces are considered valid characters.

75

If you fail to properly decode the password, the TNC will send three new lines of
numbers. You will be given a maximum of three attempts to properly decode the
password string. If you fail in three attempts, the TNC will disconnect you and disable
connects to the MYREMOTE for 15 minutes. Also, if you connect to the MYREMOTE
and start the password sequence but then disconnect, the penalty timer is in effect for
15 minutes.

Be careful when using the remote access feature. You can change ANY command in
the TNC without restriction, but this can lead to problems. For instance, if you change
the INTFACE command to KISS and then send a RESET command, the remote TNC
will be placed into the KISS mode and will completely quit talking to the radio! Also, if
you connect to the MYREMOTE of a TNC and then issue a command like CONNECT
W1ABC, the remote TNC will indeed connect to the station, but there will be no data
sent to you from that connection. The connected data would be sent to the serial port of
that remote TNC. We urge EXTREME caution when using the remote access! Note also
that any command that causes a reset (i.e. NUMNODES, PBBS, MAXUSERS) will
disconnect all current users (PBBS, NODE, and YOU).

One other minor limitation applies to receiving data from the remote TNC. When you
give any command, the response is limited to 300 characters so some commands will
not fully display their response. If you give the command DISPLAY, the full list will
begin, but you will not receive the entire list because of the limitation on this buffer.

76

PBBS (Personal Mailbox)

Introduction

Your TNC includes a Personal Bulletin Board System (PBBS), a mailbox, which is
capable of storing and forwarding messages for you and other users. This PBBS
provides the same message facilities as a computer based packet radio BBS, normally
referred to as a full-service BBS, including the forwarding of Bulletins, Private mail, and
NTS traffic (for more information on the national network of full-service PC-based
packet BBS systems, see a current ARRL operations manual).

Historical note: The first BBSs in packet radio were PC-based, using software
developed by Hank Oredson, WØRLI. A national system of packet-radio based BBSs
has developed, permitting the automatic forwarding of messages, and files, from one
BBS to another. Today, the large capacity packet radio BBSs are still PC-based, but
TNC-based BBSs now provide similar facilities, with medium capacities.

The personal mailbox is compatible with the large community bulletin board systems
(RLI, MBL, etc) and will allow them to forward mail for you directly into your TNC. You
may also place messages in your mailbox, and if the local Community BBS system
allows, your TNC mailbox will reverse forward these messages from your personal
mailbox into the community system on request. You can even set up your TNC mailbox
to automatically connect to the community BBS and forward any messages it has.

Using Your PBBS

In order to use any Kantronics TNC PBBS (even your own), first get the cmd: prompt on
your TNC, and then connect to the callsign of the PBBS. For instance, if your MYPBBS
is NØKN-1, you would connect to it simply by typing “C NØKN-1". In this example, the
PBBS is in your own TNC, so no packets would be transmitted, but you would connect

to the PBBS and receive the same prompt as if you had connected to someone else’s

PBBS.
When you connect, you will first see the message from your TNC indicating that you are

connected:

*** CONNECTED to NØKN-1

The PBBS will then send you its SID (Status ID - e.g., equipment ID) and initial sign-on
message. If a PTEXT is defined, the TNC will send it as the next line, and then send the
PBBS command prompt. For example, a Kantronics KPC-3 Plus might respond to your
PBBS connect with the following:

[KPC3P-9.1-HM$]
475000 BYTES AVAILABLE IN 15 BLOCK(S)
PTEXT would be here (if any)
ENTER COMMAND: B,J,K,L,R,S, or Help >

77

Using anyone else’s Kantronics-based PBBS would result in a similar prompt sequence.
At this point you are ready to send a message to another user, read a message to

yourself (if any has been received), or issue any other mailbox command.

Let’s assume you want to send a message to KBØNYK. You would now use the Send

Private command:

SP KBØNYK

and the TNC responds with:

SUBJECT:

Now enter a short subject line:

Just a quick question

The TNC responds with:

ENTER MESSAGE n—END WITH CTRL-Z OR /EX ON A SINGLE LINE

(where “n” is the next available message number in the mailbox).
Now you enter the text of your message (message n). To end the message and have it

saved, type a <Ctrl+Z> (hold down the control key and press Z) or type /EX. The
<Ctrl+Z> or /EX must be on a line by itself —do not type anything else on this line.
When the message has been ended properly, the PBBS responds with:

MESSAGE SAVED
ENTER COMMAND: B,J,K,L,R,S, or Help >

You may now enter more mailbox commands.
The “Mail” indicator on the front panel of your TNC blinks to alert you to unread mail

addressed to you (i.e., to the callsigns of MYCALL or MYPBBS). See the TNC
command PBLIST for how you can add other callsigns to the list of callsigns that are to

be included as “mine.” The PBLIST is also used with the PBPERSON command and the

following PBBS commands: LMINE, KMINE, and RMINE. Note that the mail-status
indicator on the front panel of the TNC is turned ON (without blinking) when someone is
connected to your PBBS.

PBBS Commands

The commands available to users connecting to your Kantronics TNC PBBS (and you
connecting directly) are as follows:

B(ye)

This command is entered by the PBBS user to disconnect from the PBBS.

E(dit) n [BPTYNFH] [>tocall] [<fromcall] [@BBS] “old” “new”

78

This command is available only to the system operator (SYSOP) or to a user at the
keyboard of a computer connected directly to the TNC (i.e., not to a remote connection,
except for the SYSOP). For an explanation of this command, see the section below on
“Editing Message Headers.”

H(elp)

Displays a HELP menu.

J(heard)

Displays a list of stations recently heard by the TNC. The list will include a date and time
stamp indicating when each station was heard.

J(heard) S(hort)

This command is similar to the J(heard) command above, but only displays the callsigns
of the stations heard.

J(heard) L(ong)

This command is similar to the J(heard) command above, but also displays any
digipeaters used by the stations it has heard and the destination callsign.

L(ist) [ x [y]] [; ]

Lists all messages in the mailbox which you are allowed to read. This will include all
BULLETINS, TRAFFIC, and any PRIVATE messages addressed TO you or sent by
you. If you are the SYSOP (keyboard or remote) ALL messages will be listed. You have
the option of specifying a beginning message (x = START #) and, if you do so, an
ending message for the list (y = END #). Also, specifying the optional semi-colon (;) in
any List command will also show the @BBS and BID (BULLETIN ID - see section on
“Sending Messages”) of the messages (if any).

L(ist) <|> call [ ; ]

Allows you to list only those messages in the mailbox which are addressed to a specific
callsign (>), or which were sent by a specific callsign (<). To list only those messages
addressed to AMSAT for instance, you would give the command

L >AMSAT.

LB [ ; ]

Lists all BULLETINS in the mailbox.

LC [cat [ ; ] ]

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Using the LC command by itself will cause the PBBS to list the TO field of all
BULLETINS in the mailbox. This will just be a list of the actual TO fields, and not a list of
the messages. If you specify a category (i.e. LC RACES) the PBBS will list the full
message headers of all BULLETINS addressed to that category.

LL n [ ; ]

Lists the most recent n number of messages in the mailbox. Again, only BULLETINS,
TRAFFIC, and PRIVATE, which you are allowed to read, will be listed.

LM(ine) [ ; ]

Lists all messages in the mailbox which are addressed to you.

LO [+|-]

This command allows you to change the order in which messages are listed. When set
to +, the messages are listed in ascending numerical order (oldest to newest). When
this command is set to “-”, the messages will be listed starting with the highest message
number (newest to oldest). This command will not be available if the SYSOP has the
PBLO command in his TNC set to FIXED.

LT [ ; ]

Causes the PBBS to list all TRAFFIC messages that are currently in the PBBS.

K(ill) n

Deletes message number n from the mailbox. You may only delete TRAFFIC
messages, PRIVATE messages addressed TO or FROM you, or BULLETINS you sent.
The SYSOP may delete any message, including BULLETINS.

KM(ine)

Deletes any messages in the PBBS addressed to you that you have read. If you have
not read a message addressed to you, it will not be deleted.

NL n

The NL (number of lines) command controls how many lines are output at a time when

a large message is read. After n lines are printed, the message “PRESS Q TO QUIT, C
FOR CONTINUOUS, RETURN FOR MORE” will appear. ‘Q’ will abort the printout of

the message. ‘C’ will cause the rest of the message to be printed without stopping.
Pressing RETURN will print the next n lines.

R(ead) n

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Reads a specific message by number. Only PRIVATE messages addressed TO you, or
sent by you, may be read, as well as any BULLETIN or TRAFFIC messages. After you
read a PRIVATE message addressed to you, the STATUS flag will automatically be set
to Y—it has been read.

RH n

The RH (Read with headers) command is a variation of the Read command. Using RH
instead of R gives you message headers as well as the other information provided by
the Read command. The message header contains the date/time the message was
received at each forwarding BBS along the path to your station.

RM(ine)

Displays all messages in the PBBS addressed to you that you have not already read.

S(end) call

Sends a PRIVATE message to the callsign specified. Using S(end) is the same as using
the SP command.

SB cat

The SB (Send Bulletin) command is used to send a BULLETIN to the PBBS.

SP call

The SP (Send Private) command is used to send a PRIVATE message to a specified
callsign. Using this command is the same as using the S(end) command.

ST zip

The ST (Send Traffic) command is used to send NTS type traffic messages to the
PBBS. Some of these commands are described in more detail below.

U(sers)

The Users command will display any other users who may also be currently connected
to the PBBS.

Sending Messages

The SEND command (and its many forms) allows the following syntax:

S call [@ bbcall[.haddr]] [$ mid]
SP call [@ bbcall[.haddr]] [$ mid]
ST zip [@ location[.haddr]]
SB cat [@ location[.haddr]] [$ bid]

where:

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 call is the callsign of the station the message is addressed to.
 bbcall is the callsign of a full service BBS to deliver the message to.
 haddr is the complete Hierarchical address designator for the BBS system or

destination of the message (see the section below on “Hierarchical Addresses”

for more detailed information). Contact your local community BBS SYSOP for
complete information on local Hierarchical addressing.

 location is the designator used for distribution of the message. For TRAFFIC,

this should be NTSxx where xx is the two letter POSTAL code for the state.

 mid is the MESSAGE ID assigned to the message by the originator.
 bid is the BULLETIN ID assigned to the message by the originator.
 zip is the 5 digit postal zip code (or postal code)
 cat is the message category. For instance, a message requesting help on a

subject may be sent to the category HELP, info sent to INFO, items for sale to
SALE, etc. Contact your local community BBS SYSOP for some other examples
and suggestions.

Some examples of commands would be:

SP WB5BBW @ W5AC.#STX.TX.USA.NOAM

This command sends a private message to WB5BBW. The message should be sent to
the W5AC BBS system, in South Texas (.#STX), which is in Texas (.TX), which is in the
USA (.USA), which is in North America (.NOAM) where WB5BBW can retrieve it.

ST 88030 @ NTSNM

This command sends an NTS traffic message to a non-ham, or to someone who is not
on packet, living in zip code 88030 which is in New Mexico. The location field contains
the NTSxx (xx = NM) to indicate that the 88030 zip code is in New Mexico.

SB RACES @ ALLUS $RACESBUL.010

This command sends a bulletin addressed to RACES, which should be sent to all BBS
system in the USA (ALLUS) and has been assigned the Bulletin ID (BID)
RACESBUL.010. This BID prevents the same message from being duplicated as it
travels throughout the BBS system.

When you send a message to the PBBS, you must include the @BBS (bbcall[.haddr])
field if you want the message to be reverse forwarded from the PBBS to a full-service
BBS system. Any message entered into the PBBS over the radio will initially be marked
with a status of H (held) and will not be reverse forwarded until the SYSOP has edited
the message header and changed the H flag. This gives the SYSOP full control over the
messages relayed by his station.

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Messages entered from the local keyboard connected to the TNC do not require editing
in order to be reverse forwarded, but must include at least an @BBS field to enable the
reverse forwarding.

Listing Messages

When you list messages with any of the LIST commands, you will get a display similar
to the one shown below. If you specify the optional semi-colon (;) you will also see the
@BBS field (if it exists) in square braces after each line.

MSG# ST SIZE TO FROM DATE SUBJECT
6 B 45 KEPS W3IWI 12/19/91 09:37:11 2 Line Element set
4 B 26 HELP WB5BBW 12/19/91 09:34:05 Xerox 820
3 T 38 66044 WØOUU 12/19/91 09:33:42 QTC Lawrence 913/842
2 PN 14 NØAPJ WØSC 12/19/91 09:33:27 AMTOR
1 B 30 ALL NØKN 12/19/91 09:32:49 Need help on AMTOR
9712 BYTES AVAILABLE
NEXT MESSAGE NUMBER 7
ENTER COMMAND: B,J,K,L,R,S, or Help

The message number (MSG#) is listed, followed by the STATUS of the message. This
status includes the message type (B=Bulletin, T=NTS traffic, and P=Personal
message). The second character in the ST column is the current status of the message.

A Bulletin status (type B) can be:

F—it has already been forwarded to another full-service BBS
H—it is being held for review by the SYSOP because it was entered into the

PBBS over the radio.

An NTS traffic message (type T) may have a status of:

H—indicating that it is being held for review by the SYSOP before it may be
forwarded.

The Private message (type P) can have the following status characters in the second
position:

H—This is a personal message that has an @BBS field but is being held for
review by the SYSOP before it may be forwarded.

N—This message is a Personal message that has not been forwarded and has
not been read by the station it is addressed to. If it is forwarded to a full-service
BBS, it will be deleted if PBKILLFW is ON.

Y—This message has been read by the station it is addressed to, but has not
been killed. It will not be forwarded even if it has an @BBS since it has already
been read.

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Reading Messages

To read a message (e.g., a bulletin such as that in the previous section listed as being
to ALL), use the READ command (see PBBS command section for details on using this
command).

Editing Message Headers

The following command can be used to edit message headers:

E(dit) n [BPTYNFH] [>tocall] [<fromcall] [@BBS] “old” “new”

This command, available only to the system operator (SYSOP), or to a user at the
keyboard, allows the sysop to edit the message headers listed below for any message
in the mailbox. You are the sysop if you can connect to the PBBS from the RS232 port.
You can also gain sysop status by connecting to the PBBS remotely (by radio); see the
section titled “Remote Sysop Access to your PBBS” for more detail.

You can change:

 The TYPE of the message:

 B — Bulletin
 P — Private
 T — Traffic

 The STATUS of the message:

 Y — Yes [it has been read]
 N — No [it has not been read]
 F — Forwarded [it has been forwarded]
 H — Held [it is not available for reverse forwarding]

Note: F and H are toggles. Entering F switches the status of the
message from F to NOTF or from NOTF to F. Similarly, entering H
switches the status of the message from H to NOT H or from NOT H to
H.

 Who the message is to or from:

 >tocall
 <fromcall

 The destination mailbox (@BBS):

 @BBS[.haddr]

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 And the subject or text of the message

When a message is listed, the “tocall” and “fromcall” appear in the TO and FROM

columns, respectively. If a message has been entered with an “@BBS” for forwarding,
the complete hierarchical address is shown when the message is read:

MSG2 02/10/92 10:30:58 FROM KBØNYK TO HELP
@wa4ewv.#stx.tx.usa.noam

The @BBS is also listed when using the semi-colon (;) option with any of the list
commands.

You can access the Edit command by connecting to the mailbox from the attached
terminal, or by connecting over the radio. If you connect over the radio, you must gain
SYSOP privilege by giving the SYSOP command. When you give the SYSOP
command, the PBBS will send you a password verification string, which must be
properly responded to in order to gain SYSOP access. This is explained in detail later.

Let’s say you want to edit message number 2 which currently is a PRIVATE message
addressed to WØXI. The message has been read by WØXI so it shows a status of Y. It
may list as:

MSG# ST SIZE TO FROM DATE SUBJECT
2 PY 53 WØXI NØKN 01/14/92 03:36:45 Good afternoon

Let’s say you want to change this so that it is addressed to NØGRG and also change

the Y flag to N to show that it hasn’t been read. To do this, you connect to your PBBS

(either from the KEYBOARD or as SYSOP over the radio), and issue the command:

e 2 N >NØGRG

You could do this with two separate commands, or it may be accomplished with the
single command shown above.

You can change a subject or text in the message by entering two strings in the Edit
command. The first occurrence of the string “old” will be replaced by the string “new”.
For example, to change the subject from Good afternoon to Good morning:

e 2 “afternoon” “morning”

Hierarchical Addresses

Hierarchical addresses (explained below) are used to accommodate the national packet
traffic system, including messages processed by PC-based packet radio BBSs.

The HTEXT command allows you to set your Hierarchical address. This is used
whenever your PBBS forwards mail to another BBS to provide complete return
addressing capability. Other PBBS features include the ability to select whether or not to
kill private and traffic messages after they have been forwarded, and whether or not to
HOLD messages received over the radio.

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A hierarchical address consists of your state, country, and continent codes, separated
by periods. Some areas (in large states particularly) use sub-state designators. For
instance, a station in Rhode Island might use a hierarchical address of RI.USA.NOAM.
This means Rhode Island (RI) which is in the United States (USA) which is in North
America (NOAM). In this case, you should set the HTEXT to RI.USA.NOAM. If you are
unsure of your hierarchical address, contact your local packet BBS sysop and ask what
the proper addressing is for your location.

The PHEARD command will show you the callsigns of stations recently connecting to
your mailbox along with their start and stop times.

Advanced Configuration of Your PBBS

When you first enter your callsign into the TNC, your PBBS will automatically be
enabled. The MYPBBS callsign is set to your basic call with an SSID of -1, and the
PBBS is allocated 100 k bytes of RAM (assuming you have the standard 128 k byte
RAM chip installed).

You may change the size of the PBBS using the PBBS command. The maximum
amount of memory you can allocate will depend on the amount of free memory
available. NUMNODES, MAXUSERS, and MYREMOTE, etc., will affect the amount of
available memory.

If you change the size of the mailbox, the TNC will not renumber any existing
messages, and if the new size is large enough for all existing messages, no messages
will be lost. If you want to renumber the messages (starting with 1) give the PBBS n
command with n being the current size (i.e., n kbytes of memory assigned to the PBBS).



To see the current size of the mailbox, enter the command “PBBS” (without any

number) at the Command prompt.

You can also change the maximum number of users who can connect to the PBBS at
the same time. PBUSERS will cause a reset if it is changed.

At times, you may be away from your computer and would like to switch a user into your
mailbox automatically if he connects to your MYCALL. This can be accomplished by
setting the CMSG command to PBBS. When this is done, a user who connects to your
MYCALL will be sent your CTEXT (if any) and then be automatically connected to the
PBBS. The TNC will then send the PBBS System ID (SID) and sign on message. The
SID is enclosed in square brackets and consists of the unit name, firmware version, and
the supported feature set.

For example the Kantronics KPC-3 Plus SID is:

[KPC3P-9.1-HM$]

This is the unit name (KPC3P), version number (9.0) and the feature set (HM$). The H
means it supports Hierarchical forwarding, the M stands for Message ID, and the $
indicates BID support. These identifiers are the SID definitions published by Hank
Oredson (WØRLI) with his Community BBS system.

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You can customize a greeting message to be sent to a user who connects to your
PBBS by using the PTEXT command. This command accepts up to 128 characters as a
text string to be sent to the user immediately after the SID is sent.

If it becomes necessary to disconnect a station from your PBBS, you can use the local
terminal connected to your TNC to accomplish this (see DISCONNECT MYPBBS). If a
station connects to your PBBS and no activity occurs on the connection for 15 minutes,
the PBBS will automatically disconnect the user in order to make your PBBS available
to others.

Note: To get forwarding or reverse forwarding, you need to have HTEXT set. HTEXT
specifies your Hierarchical address, which is needed for complete return addressing
capability.

If a community bulletin board forwards messages into your PBBS, it sends you many

lines beginning with “R:”. These are routing headers that show the complete path taken

by this message. By default, these headers will be stored in your PBBS with the
message. If you choose, you may prevent your PBBS from storing these by setting the

PBHEADER command OFF (for more information, see the section below titled “Routing

Lines”).

If you want your PBBS to only accept messages for you, you can set the PBPERSON
command ON. When set ON, this command will make your PBBS only accept
messages that are addressed to your MYCALL, MYPBBS or PBLIST.

Finally, the PBLO command is used to determine the order in which messages are
listed to a user. When PBLO is set to OLD, messages will be sent oldest first (message
1, then 2, etc). When set to NEW, the most recent message will be listed first. The
second parameter of this command determines whether or not you will allow a PBBS
user to change the listing order while he is connected. When set to FIXED, the user
cannot change the order, and when set to VARIABLE, the user may change the order
by connecting to the PBBS and using the LO command.

Remote SYSOP Access to the PBBS

You can gain remote SYSOP access to your PBBS (e.g., to edit messages, using the
EDIT command) by first connecting to your PBBS and then entering the SYSOP
command. When you enter the SYSOP command, you will receive three sets of
numbers from the PBBS. These numbers indicate the character positions of the RTEXT
to be used as the password for logging on for this remote access.

For instance, let’s say your RTEXT is:

This is a sample rtext.

Now when you give the SYSOP command, the TNC might respond with:

1 12 3 18 6 9
2 10 22 5 7 18
13 16 4 9 1 20

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If you choose the first set of numbers, you should send the following as a response:

Tairia

(T is the 1st letter, a is the 12th letter, i is the 3rd letter, and so on. See the RTEXT
command in the Commands section for a more detailed explanation.)

NOTE: Spaces DO count as characters, and case is significant!

Reverse Forwarding Messages from Your Mailbox

The TNC mailbox will allow you to enter messages, which will be forwarded by full­service BBSs (RLI, MBL, etc). These messages have a special format, and can be
entered in any personal mailbox. Let’s suppose you want to send a message to
WA4EWV who lives in Texas. You know his home BBS is WB5BBW, so you can put
this message in the PBBS with the command:

S WA4EWV @ WB5BBW

Entering an @ BBS will cause the TNC to reverse forward this message to a full service
BBS when requested by the full service BBS. In order to improve the chances of this
message reaching its destination, you should always enter the message with complete
hierarchical forwarding:

S WA4EWV @ WB5BBW.#STX.TX.USA.NOAM

Complete information on Hierarchical forwarding can be obtained from your local BBS
system operator, but basically the first field after the @ symbol is the HOME BBS of the
station you are trying to send a message. The next several fields (separated by periods)
are the state (two-letter postal abbreviation), country, and continent. In this case, since
Texas is so large, it is sub-divided into smaller areas. These are indicated with the #
symbol (in this case #STX—South Texas).

Messages entered into your mailbox in this format will be reverse forwarded to the full
service BBS when requested, and the following rules apply:

The TNC acts like a “smart BBS” when forwarding to or from a full service BBS. This

means that it will no longer send the SUBJECT: prompt, nor will it send the ENTER
MESSAGE prompt. You will also notice that when a full-service BBS connects to your
PBBS, the TNC does not send the usual ENTER COMMAND prompt, but only the > is
sent. This is designed to reduce the amount of data on the packet network, since
“smart” BBSs know what is expected of them.

Once a Private or Traffic message has been successfully forwarded out of your mailbox,
it will be deleted from the PBBS if PBKILLFW is ON. Bulletins will be marked with a
status of “F” and will remain in the PBBS.

Selecting a Home Full-Service BBS.

One important use of your Kantronics PBBS is to connect to the national system of
packet-radio based BBSs, which was described earlier in the “historical note” at the

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beginning of the PBBS section. You can use a “home” full service BBS for sending and
receiving mail, much as you would use a P.O. Box at a postal facility. The full-service
BBS should always be on and available to handle mail for you.

Each PBBS user should select one (and only one) PC-based, full-service BBS for
sending and receiving mail. This BBS is then called your HOME BBS and should not be
changed unless you move to a new location. When you connect to your home bulletin
board system and list the messages (using the L command), you will see a list
containing information about each message on the system. A list of messages on one
local full-service system might look like this:

Msg # TSL Size To From @ BBS Date/Time Subject
====== === ==== ===== ====== ======= ====/==== =======
59765 B$ 1491 NASA N5IST ALLUS 1004/1529 GALILEO STATUS 09/30/93
59764 BNL 468 WX N0NEJ 1012/1017 KC Forecast 10/12 400am
59763 BNL 659 WX N0NEJ 1012/1017 MO Forecast 10/12 400am
59759 B$ 2240 NASA N5IST ALLUS 1004/1529 MARS OBS. STATUS 9/27/93
59758 B$ 1642 NASA N5IST ALLUS 1004/1529 MARS OBS. STATUS 9/22/93

This list shows the message number, type and status information, the size of the
message, the addressee (TO field), the originator (FROM field), and the @BBS field. In
addition the list shows the date and time the message was received at this BBS and a
short subject for the message.

Routing Lines

Under current FCC requirements, BBS systems that can store and forward messages
without an operator being present must have the capability to provide a record of the
path the message has taken from its origination. To accomplish this, BBSs include a

routing line, beginning with “R:”. This “R:” line includes the date and time the message

was received, message number, BBS call and hierarchical routing information.
When you read a message using the R command (e.g. R 59765) you see the header

displayed. For example:

From : N5IST
To : NASA @ALLUS
Type/status : B$
Date/time : 04-Oct 15:29
Bid : NASA0930.GAL
Message # : 59765
Title : GALILEO STATUS 09/30/93
Path : !NØKN!N0LLY!N0OER!N0OBM!NX0R!AG0N

!N7MMC!KT0H!KA0WIN!N5IST!

The Path: statement in the header lists the most recent BBS systems that have been
used to relay this message from its origin to the BBS you read it from. This path
information is required by the FCC to allow them complete traceability for any message
in the system. What you see in the PATH statement is not the complete information on

the routing, but simply a summary of the systems that have handled the message. To
see the complete information, BBS systems allow a second version of the READ

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command (RH or V) that will display more routing information. A routing list from a
bulletin appears below.

R:931012/1107 27268@NØKN.#NEKS.KS.USA.NOAM
R:931012/1025 16433@N0LLY.#NEKS.KS.USA.NOAM
R:931011/2021 928@N0OER.#NEKS.KS.USA.NOAM
R:931008/1814 20728@N0OBM.#NCKS.KS.USA.NOAM
R:931008/2003 19520@NX0R.#NKS.KS.USA.NOAM
R:931008/1153 30798@AG0N.#WNE.NE.USA.NOAM
R:931007/1147 35850@N7MMC.#SEWY.WY.USA.NOAM
R:931007/1712 49403@KT0H.#NECO.CO.USA.NOAM
R:931007/1639 63792@KA0WIN.#SECO.CO.USA.NOAM
R:931004/1529 46383@N5IST.#WTX.TX.USA.NOAM

By examining this list from the bottom up, we may see that the message entered the
system on October 4, 1993 at 15:29 (R:931004/1529). It was message number 46383
on the N5IST BBS (@N5IST) which is located in West Texas (#WTX), which is in Texas
(TX), which is in the United States (USA) which is in North America (NOAM). From this
station, it was relayed on October 7 at 16:39 to the KA0WIN BBS in Southeastern
Colorado. By following this information it is possible to determine where the message
traveled and when it was relayed from each station. The information following the
@BBS callsign is called the hierarchical routing information (in this case
#WTX.TX.USA.NOAM).

When you connect to your local BBS and send a message, that BBS automatically
generates this R: line. As the message is sent to its destination, each BBS adds its own
R: line to the message. Besides the requirement of the FCC, the R: line provides a
method for any user, anywhere in the world, to send a reply or respond to your
message. As the message is passed through the many BBSs, each BBS will add you
into its White Pages —a directory of packet users. Each BBS makes note that you (the
originator of the message) sent the message, and that you entered the message at the
BBS listed in the last R: line in the message.

Because of this, a distant user can simply send a reply using the send reply (SR)
command of his local BBS. That BBS will then address the message to you using the
@BBS and hierarchical routing information in the last R: line of the message you sent. A
user may also simply use the send private command (SP) to send a message to you. If
the user does not enter complete addressing on his SP command, the BBS will attempt
to look up your call in its White Pages and add the routing automatically. However, if the
user supplied complete addressing information, the BBS would normally assume it is
correct and not check the White Pages.

BBSs use this hierarchical information to send the message back to you. The message
someone sent to you (using the above example) would be addressed to URCALL@
N5IST.#WTX.TX.USA.NOAM. As the message passes through the BBS system for
forwarding, the BBS first looks at the callsign of the addressee (URCALL). If that BBS

doesn’t know how to forward the message to you, it then looks at the @BBS field
(N5IST). If it doesn’t have any information on how to forward to N5IST, it looks at the

first part of the hierarchical address (#WTX), not knowing that, it would then look at the
next part of the hierarchical address (TX). Assuming this BBS is in the United States, it

90

knows TX means Texas and knows that this message needs to be relayed to a station
in that area.

Once the message reaches the first BBS in Texas, that system must use the previous
field for forwarding (#WTX). Once it reaches a system in West Texas, the forwarding
occurs based on the @BBS.

When the message reaches the BBS specified in the @BBS field, it can forward the
message directly to you, since you are using that system as your HOME BBS.

When you enter a message into your Kantronics PBBS and supply the routing
information, that message may be forwarded automatically to another BBS. When the
message is forwarded from your Kantronics mailbox, an R: line is included as the
originating BBS. This line includes the same information as any other BBS.

This R: line consists of the date/time the message was entered into your PBBS, the
message number, your MYCALL (URCALL) and the HTEXT you have set.

For instance, your R: line might be:

R:931008/1255 23@URCALL.#WTX.TX.USA.NOAM

Some BBS operator groups are insisting that your system is NOT a BBS, and therefore
should not include R: lines. Their reasoning is that in the above example, EVERY BBS
in West Texas would have to know how to send messages to your callsign not just to
your HOME BBS. One solution to this is to include the callsign of your HOME BBS as
part of your HTEXT. This would change your R: line to:

R:931008/1255 23@URCALL.N5IST.#WTX.TX.USA.NOAM

As this forwards through the system, all West Texas BBSs can still forward the
message to N5IST because his call is a part of the hierarchical routing.

As of this writing, there seem to be at least two groups with strong opinions on the use
of, or prohibition of, R: lines by TNC based PBBSs. Some think the volunteer BBS
network may be overloaded by personal boards including the R: lines; others insist that
the R: lines are required by regulations. We suggest you adapt to local custom by
turning the R: line feature ON or OFF accordingly.

If your local SYSOP demands that you not add R: lines to your messages, you must set
the PBPERSON command ON. This will limit your PBBS to receiving messages
addressed ONLY to your MYCALL or your MYPBBS call. In addition, your PBBS will
only forward messages from YOU (no third-party messages) and will not add the R: line
to the routing.

Hint: When you read messages with the normal READ command, the TNC will not
display those R: lines, but instead will display a short PATH: line, indicating the most
recent BBSs that have handled this message. If you want to read the full routing, use
the RH command to read the message with all the headers displayed.

This concludes the section on PBBS mode of operation.

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GPS NMEA Interfacing

Most Kantronics’ TNCs, e.g. KPC-3 Plus, KPC-9612 Plus, KAM XL, and others, support
the GPS mode, explained below. Each contains firmware to interface with a GPS device
supporting the NMEA 0183 interface standard; commands to configure and control
unproto (path) retransmissions of the NMEA strings, and provides RAM storage for
location messages (strings) for later retrieval.



Among Kantronics’ TNCs supporting GPS, the only difference between devices is
the number of radio ports available for transmission of data. For example, the KPC-3
Plus is a single port device and the KPC 9612 Plus is a multi-port device.

Overview

The Global Positioning System (GPS) was developed initially for military use by the U.S.
Department of Defense, to provide worldwide positioning and navigational information
for U.S. military forces. Since then, a broad range of commercial, civilian, and amateur
radio applications have been developed, based on the GPS. The GPS consists of 24
satellites, each of which transmits positioning information continuously. GPS receiving
units - devices that contain a receiver, LCD screen, and (usually) a data port - collect
this positional information and use it to compute position. This information can then be
retransmitted by any means possible to report the position of the GPS unit (and its
vehicle).

Most GPS units sold today are NMEA compatible. That means that not only can they
display latitude, longitude, and time on a LCD screen, but the information can be

presented to your computer or TNC via the GPS unit’s serial data port. The information
is presented in ASCII in the form of NMEA “sentences”. A number of these sentences

are available —with varying kinds of information, but the one used most often for

amateur radio activities is “$GPGGA”. This sentence contains latitude, longitude,

altitude, and time (in UTC, derived from the satellite clocks). The TNC, in GPS Mode,
can receive and retransmit this information as beacons and/or store these sentences in
a large tracking buffer for later retrieval. The TNC, in GPS Mode, also updates its clock
to UTC, derived from the satellites. Hence, the location of your remote packet station,
recorded at a specific time, can be tracked by other packet stations.

Amateurs the world over have discovered GPS and are combining this exciting new
technology with packet radio for reporting the position of their vehicles, following balloon
launches, finding hidden transmitters, and determining location information for more
serious applications as well. A typical amateur location reporting system consists of
GPS-packet equipped vehicles and fixed-location packet repeaters. At a minimum, each
vehicle would carry a GPS receiver, a packet unit (TNC), and a transmitter. Each TNC,
in GPS mode, would be set to beacon location periodically. The fixed-location

digipeaters would relay the reporting stations’ locations over a wide area. For more

details on setting up such a system, see the next section, on “Advanced Digipeating.”

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GPS Equipment (or weather station) Requirements

To set up a packet GPS station that can be tracked, you’ll need the following

equipment:

 a transceiver and antenna,
 A Kantronics TNC that supports the NMEA 0183 interface standard.
 a GPS unit with an NMEA interface and portable or external antenna. More than

50 vendors produce GPS units and most offer NMEA data interfacing which is
essential.



Over time, a number of software programs will be developed by amateurs to use packet
and GPS. One shareware program that has emerged already is the Automatic Packet
Reporting System (APRS), written by Bob Bruninga. An APRS system may consist of a
GPS unit, a computer, and (optionally) a packet unit. In APRS, NMEA data, from a GPS
unit, is passed to the computer, and it is the computer’s job to display the information
and, if desired, transmit that location via a packet unit using unproto packets.



In some applications, you may wish to keep your PC or terminal attached to the TNC for
packet operations, yet switch serial port connection to the GPS unit periodically—just to
update your location. This arrangement is handy when only one COM port is available
on your PC. This can be accomplished with an APRS-HSP cable and APRS software.

Cabling a GPS Unit to a Kantronics TNC

The NMEA standard specifies that the signals in the GPS receiver data port follow the
EIA-422 standard.

Technical note: Many GPS vendors simply use “TTL” voltage levels (+5 V and 0 V), but

use the same polarity as RS232. These units are capable of driving a Kantronics TNC
RS232 serial data port input pin. However, some GPS vendors invert the sense of this
signal (true TTL), and these units will not directly interface with a TNC.

Warning: The Kantronics TNC serial ports are RS232; that is, they provide for signals
that swing plus and minus approximately 8 V. Check your GPS manual before
connecting this port to your GPS device to make sure that it is capable of handling
these voltages. Kantronics is not responsible for damage wherein its TNCs are attached
to other devices; see the Kantronics Limited Warranty.

To connect the data port of a GPS unit to your TNC, you’ll need a three-wire cable. A
shielded cable is preferred. Refer to your GPS manual to determine which pins are used
for signal ground, data output to an RS232 device, and data input from an RS232
device (such as the TNC). At least two of these wires must be connected at both ends
of the cable:

 connect the signal ground wire of the GPS data port to pin 7 of the TNC serial

port. This wire may be identified as “NMEA-” by some GPS vendors.

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 connect the “data output pin” of the GPS data port to pin 2 of the TNC serial port.

The data output pin may be identified as “NMEA+” by some GPS vendors; this is

the line that supplies the NMEA sentences to your TNC.

Some GPS units may allow for programming of parameters. If so, this is accomplished
by passing commands to the GPS unit from a terminal (or TNC) via an additional pin in
the data port.

If your GPS unit accepts the setting of parameters, you may wish to connect the third
wire of your cable from the input data pin of the GPS data port to pin 3 of the TNC serial
port. Again, consult your GPS manual for the name of this pin; names vary by vendor.
Also, make sure this pin will accept an RS232 signal (+ and – voltages).

Alternate GPS Input

In the KPC–3 Plus, an alternate input for GPS data was added in firmware version 8.3.
This input is pin 2 on the KPC–3 Plus’ “Radio” port, and is enabled with the KPC
command GPSPORT. A data signal ground is also required, which is pin 6 on the

“Radio” port connector, or pin 9 (if internal jumpers are set to configure pin 9 as a

ground connection).
Note: The default function for pin 2 on the KPC radio port is XCD (external carrier

detect). If pin 2 on the KPC radio port has been connected to a GPS device, and
GPSPORT has been configured for GPS input on this pin, the XCD function is not
available.

Configuring a Kantronics TNC for GPS Operation

To configure your Kantronics TNC in GPS Mode you must set several command
parameters from your PC keyboard as follows:

 select the GPS strings you will be capturing in each of the Location Text buffers
 set the beacon rates for each Location Text buffer you are using
 enter the unproto paths for each Location Text buffer you are using

You determine which GPS strings will be stored in the Location Text (LT) buffers by
entering the string header with the GPSHEAD command. The TNC searches for specific
strings of data from the GPS unit and stores them in up to four LT buffers. These LT
buffers may then be transmitted at periodic intervals as a beacon. The frequency of the
beacons is controlled independently for each LT buffer, by the BLT command (which
stands for Beacon Location Text). You may also set the destination address and the
path for each of the four LT beacons independently using the Location Text Path (LTP)
command.



If the GPSHEAD string for any LT buffer is empty, that LT buffer can be set up as an
auxiliary beacon; LT, BLT, and LTP are used like BTEXT, BEACON, and
UNPROTO.

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In addition to transmitting the beacons periodically, your TNC can store the transmitted
beacons in a location buffer (LTRACK) for later review. The size of the LTRACK buffer
is set by a command from the keyboard.

Setting Parameters in the TNC



To add GPS capability to your portable packet station, enter the required GPS
parameters into your TNC (from your PC), set ABAUD to 4800, and then cable your
TNC to the NMEA data port of your GPS unit.

Note. Most GPS units have a fixed NMEA data port rate of 4800 baud; however, some
advanced units allow other bauds.

To set up your TNC for GPS operation, you must first be communicating with it via your
terminal in the normal mode (Command Mode or with a Host Mode program).

First, set the GPSHEAD command to capture specific sentences from the GPS unit.
You can set up to four strings to be stored (one each) in the LT buffers. The command
would be GPSHEAD n string where n is the LT buffer number, and string is the name
of the GPS string to be stored.

For instance, if you want the TNC to store the $GPGGA string in LT buffer number 1,
use the command:

GPSHEAD 1 $GPGGA

In order to beacon an LT buffer, you must set the LTP and the BLT commands for that
LT buffer. Full details of the LTP and BLT commands can be found in the commands
section, but here’s an example of how they could be used:

If you want LT 1 to beacon with a path of GPS via a digipeater (called DIGI), and you
want the beacon to occur every 30 minutes, use the following commands:

LTP 1 GPS via DIGI
BLT 1 EVERY 00:30:00



Several amateur groups, such as APRS (see the bibliography at the end of the GPS
section), have developed special programs for enhancing amateur GPS activities.
Check with them for current practice in setting GPS beacon paths, beacon rates,
and frequencies used in your area.

You can also set up a “tracking buffer” to store the most recently transmitted LT

information for later retrieval. The size of the buffer and which LT buffers to store is
controlled by the LTRACK command. For instance, the command

LTRACK 5 LT1 LT2

would set the size of the LTRACK buffer to approximately 5 kbytes and store the LT 1
and LT 2 buffers whenever they are transmitted (as set by the BLT command).

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GPS Unit Initialization from the TNC

Some GPS receivers require reception of a special string of characters for initialization
before they will send any information. You can tell your TNC to send the initialization
string to your GPS unit by entering the required string using the GPSINIT command. For
instance, if your GPS receiver requires the string $PGRMO,GPGGA,1 to be sent, you
would give the command

GPSINIT $PGRMO,GPGGA,1

to your TNC. Upon power up, the TNC will then send that string via its serial port to the
GPS unit (when the TNC INTFACE command is set to GPS.)

GPS Operations

Starting the TNC in GPS Mode



Hint: Be sure to set ABAUD to that required by your GPS unit.

Once you have the TNC parameters set for GPS, you need to set the TNC to start in
GPS Mode on power up. To do this, set the INTFACE command to GPS. When the
TNC resets (either from a RESET command or by turning the TNC off and then on) it
will be in the GPS Mode and the GPSINIT string (if any) will be sent to the serial port.

Normally, you would set the INTFACE command to GPS, turn the TNC off, connect your
GPS unit, and then turn the GPS unit ON and then turn the TNC ON.

When operating in the GPS Mode, the TNC will automatically update the LT buffers
every time it receives the designated NMEA strings from the GPS receiver.

Exiting GPS Mode

If you want to exit the GPS Mode (perhaps to set new parameters), connect your
computer or terminal to the serial port of the TNC and type three <Ctrl+C> characters.

The TNC will reset and the INTFACE command will be set to TERMINAL.
Hint: You may have changed the ABAUD setting (usually to 4800) for the GPS mode. If

so, before you can use the three <Ctrl+C> characters to exit GPS mode, you must set
your RS232 baud in your computer to the same as the ABAUD setting in your TNC.

Other GPS Features

Slotted Beacons

The BLT command provides for the ability to specify not only the interval between
beacons, but a starting time for the beacons. This permits a “slotted” system of beacons
by numerous stations. For instance, lets say your local area has 30 stations that each
should beacon their location every 30 minutes. A beacon would be transmitted every n

96

minutes from the time the user sets the time that the beacon should be transmitted. As
an example, if you set the BLT command for LT 1 (BLT 1) with the command:

BLT 1 EVERY 00:30:00 START 00:00:01

the TNC would transmit a beacon at 00:00:01 (time after midnight) and every 30
minutes after that. The second user could set the BLT with the command:

BLT 1 EVERY 00:30:00 START 00:01:01

In this case, these two users would never beacon at the same time, in fact they would
beacon 1 minute apart. Using this system for our example, it is possible to set all thirty
users to beacon one minute apart, avoiding collisions.

Tracking without Beacons

You may configure the TNC to store the LT “beacons” in the LTRACK buffer without

transmitting the beacons. To do this, set the LTP to NONE for the associated LT buffer:

LTP 1 NONE

When the destination call (path) is set to NONE, the TNC will not transmit the beacon,
but since the BLT command is still active, the data will be stored in the LTRACK buffer.

Remote Access and GPS

When the TNC is in GPS Mode, the serial port is expecting data only from a GPS unit,

hence, it cannot process any “normal” commands. Should you need to change any of

the TNC commands, however, there are two options: 1) exit the GPS Mode using a
terminal, or 2) connect to the TNC remotely by radio (MYREMOTE) and change the
commands.

When you connect remotely to the TNC (and properly respond to the password security
check) you can change any parameters including the GPS parameters. You may also
wish to send a command string to your GPS unit. This is accomplished with the RPRINT
command. For example, to send the string $PGRMO,GPGSA,1 to the GPS unit,
connect to the MYREMOTE of the TNC, verify the password, and send

RPRINT $PGRMO,GPGSA,1

to the MYREMOTE. The TNC simply sends this string to its serial port (which is
connected to the GPS receiver).

Other Notes

The LT buffers, LT beacons and LTRACK buffer can be used even without a GPS unit
attached. You can manually set the LT buffers to any text you want (up to 128
characters total) using the LT command:

LT 1 This is ltext buffer number 1

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The LT buffers will be transmitted based on the BLT and LTP commands and stored
according to the LTRACK command even when the TNC is not in GPS Mode.

GPS Command Summary

The following GPS commands are listed here for convenience and explained in detail in
the Command Reference section.

BLT n{EVERY | AFTER} hh:mm:ss [START hh:mm:ss] (n = 1 - 4)

This command sets the interval between beacons for the associated LT string.

GPSHEAD n string (n=1-4) (string up to 8 chars)

This command determines which GPS NMEA sentences will be stored in the LT buffers.

GPSINIT string (string up to 128 characters)

This command establishes a string that will be sent to the attached GPS unit upon
power-up (i.e., initial text sent to terminal in GPS Mode).

LT n text (n = 1-4) (text up to 128 chars)

This command fills the specified location Text (LT) buffer with “text”.

LTP n dest [via call1[,call2,...]] (n=1-4)

This command sets the destination callsign and the digipeaters used to transmit the LT
strings.

LTRACK n [LT1] [LT2] [LT3] [LT4] [SYSOP] [TIME]

This command allocates memory for a special tracking buffer used to store LT
messages.

RPRINT text (text up to 128 characters)

This is an immediate command which sends the “text” string from the serial port of the
TNC to the attached device (e.g. GPS unit).

Also, see the GPS setting for the INTFACE command. When this command is set to
GPS, the TNC will enter GPS mode upon power up. Data from the serial port will be
parsed according to the GPSHEAD command, text will be placed into the LT buffers,
and beacons will be transmitted according to the setting of the BLT commands.



Hint: To have the TNC exit GPS Mode, connect a PC or terminal to it and issue
three <Ctrl+C> characters.

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Advanced GPS (or APRS) Digipeating

The “UI” digipeating commands described in this section add flexibility in reporting GPS

(or APRS) station positions. It is an established procedure of the reporting stations to
digipeat with generic callsigns and through a number of repeaters (e.g., “APRS”
repeaters). In this way, reports of their positions can reach out, via a number of
digipeaters, to any wide area. At the same time, the digipeaters supporting these
activities must establish their TNC parameters such that all UI frames “copied” are
digipeated often enough (enough repeats of each frame), but not too often (too many
repeats of each frame), to achieve the desired result.

The commands introduced here (i.e., UIDIGI, UIFLOOD, UITRACE, and UIWAIT) allow
each digipeater owner a wide range of ways in which to configure their TNC (in
cooperation with other digipeaters in a network, who all need to work together) to
establish an optimum GPS (or APRS) repeating network.



Note: This section assumes you are familiar with GPS, digipeating, and APRS (each
topic is discussed elsewhere in this manual). For details about APRS (A Packet
Reporting System) developed by Bob Bruninga, WB4APR, consider obtaining a
copy of “Getting On Track with APRS,” by Stan Horzepa, 157 page paperback,
published in 1996 by the ARRL, 225 Main Street, Newington, CT 06111.

Amateurs are using GPS receivers, a packet unit, and an FM transmitter to report the
location of their vehicles or stations to others. Their broadcasts use one-way (unproto
UI) packets, reporting call sign, latitude and longitude. Packet stations hearing these
broadcasts can monitor the location of the vehicles.

A common goal of these position reporting stations is to digipeat a UI packet over a
wide area (or a long distance), while moving though areas where the local callsigns may
be unknown. An effective solution for not knowing local callsigns is to establish standard
generic callsigns for digipeating stations and then use these names in digipeating paths.
Of course, this requires the acceptance and use of standards for naming and using
digipeating stations, by both the position reporting stations and the digipeating stations.



Common standards have been established by some local APRS groups, with names
such as RELAY, WIDE, and TRACE. We encourage you to contact your local GPS
(or APRS) interest group before configuring your TNC with its new digipeater
capabilities. Usage may vary by area.

Improving Efficiencies of Advanced Digipeating

As described above, mobile location reporting stations are using digipeating paths
containing generic digipeating names (e.g., RELAY, WIDE, TRACE) to extend their
range of reporting. Using generic digipeating enables a mobile station to use the same
digipeating path as it moves around, since there will (presumably) always be nearby
GPS (or APRS) digipeating stations with one or more of these generic names to pick up
transmissions (i.e., UI packets) and re-transmit them to a wider area.

99

Using generically named digipeaters does result in wider coverage of GPS stations, but
several inefficiencies may arise from this common practice (depending upon the
availability and names of the digipeaters).

Among the problems that may arise in this situation are that: (1) UI packets can be
repeated much more than necessary, by the same or by different digipeating stations
with the callsigns RELAY, WIDE, or TRACE clogging up the airwaves, and that (2)
several stations may re-transmit the same packet at the same time, resulting in a
combined signal that cannot be copied by other stations.

Kantronics’ TNCs have a suite of UI digipeating commands that can be used to deal

with inefficiencies that can arise when a number of digipeaters are transmitting in the
same area, at the same time, using the same generic names.

Overview of UI Digipeating Commands

The following UI digipeating commands support advanced GPS (or APRS) digipeating
capabilities.

The UIDIGI command may be used to set up to four additional aliases/call signs for
“special” digipeating service. To-be-digipeated packets received containing one of these
aliases will be repeated (once) with the call sign (MYCALL) of the digipeater substituted
for the alias in the digipeated frame. See the example shown below and the command
description for more detail.

UIFLOOD and UITRACE are a bit more exotic. Each provides for multi-hop digipeating
with just one digipeater address per packet, thereby keeping the transmission time
short. For example, to digipeat through three TNCs supporting the UIFLOOD command,
the reporting station might set a GPS position path as follows:

LTP 1 GPS via wide3-3.

A digipeater TNC supporting “wide” set by the UNIFLOOD command and hearing the
reporting station’s transmission would then digi the UI location packet (assuming it had

not done so already, within a preset time), using an address of wide3-2. In turn each

similar digipeater down line would digi the reporting station’s UI packet and reduce

(decrement) the ssid of the digipeater address again. A TNC using UIFLOOD has the
option of inserting MYCALL, creating two rather than one digipeater addresses in each
transmitted digi packet.

With UITRACE, each time a packet is digipeated, each TNC adds its MYCALL, thus

creating a “trace” or return path. In effect, the size of the packet grows by one

digipeated address with each hop. A parameter, n, sets a delay time “do not digipeat

within n seconds.” Again, see the examples below and the command descriptions for

detail.
The current setting of UIDWAIT determines whether or not a delay is added to UI

digipeat packets (those formed by UIDIGI, UIFLOOD, or UITRACE) before
transmission, once the channel is clear. If UIDWAIT is ON, the delay is determined by
slottime or persist settings.

100

The purpose of the UIGATE (which is in multi-port devices only) is to prevent heavy

high speed UI frame activity from congesting (“flooding”) the low speed (port 1)

frequency.
Each of these commands is documented in the “Command Reference”.
Note: Digipeater priority for call signs is as follows: UIDIGI, UIFLOOD, UITRACE,

MYCALL, MYNODE, MYALIAS (e.g. if you assign the same call sign to UIDIGI and
MYALIAS, a to-be-digipeated frame with that call sign will be digipeated according to
the rules that apply to UIDIGI).

Using “UI” Digipeat Commands: UIDIGI, UIFLOOD, and UITRACE

The following are actual monitored outputs of a lab system consisting of one position
reporting station and three digipeaters, where each digi is configured using the UIDIGI,
UIFLOOD, or UITRACE command and where UIDWAIT is set ON. We set UIDWAIT
ON to force the system to digipeat all or most of the UI frames without collision. In all
examples, the reporting station, WØXI, is used to launch a UI packet with the path set
by the UNPROTO command.

With UIDWAIT OFF, several digipeaters would transmit at the same time, resulting in
corrupted packets. In actual on-the-air use, a system of digipeaters may work well with
UIDWAIT OFF, depending upon their mix of location and transmitter power.



In actual use, GPS (or APRS) reporting stations would set their path with the LTP

Configuring Three Digis Using the UIDIGI Command

Here, three digis, with MYCALLs of A, B, and C, are configured with aliases of RELAY,

WIDE, and TRACE (using UIDIGI); and UIDWAIT is set ON. For example station A’s

UIDIGI aliases are set as follows:

cmd: UIDIGI ON RELAY, WIDE, TRACE

The reporting station path is then set to GPS via RELAY, WIDE, TRACE, and a UI
packet is launched.

Any one of the stations monitoring will then display the resulting action as follows:

cmd: WØXI>GPS,RELAY,WIDE,TRACE: <UI>:5
WØXI>GPS,B*,WIDE,TRACE: <UI>:5
WØXI>GPS,A*,WIDE,TRACE: <UI>:5
WØXI>GPS,B,A*,TRACE: <UI>:5
WØXI>GPS,A,B*,TRACE: <UI>:5
WØXI>GPS,C*,WIDE,TRACE: <UI>:5
WØXI>GPS,B,C*,TRACE: <UI>:5
WØXI>GPS,A,C*,TRACE: <UI>:5
WØXI>GPS,B,A,C*: <UI>:5
WØXI>GPS,A,B,C*: <UI>:5
WØXI>GPS,C,A*,TRACE: <UI>:5
WØXI>GPS,B,C,A*: <UI>:5