ZyXEL Communications 2864 User Manual
2864 Series Modem
User’s Manual
Document No.: 8406, Rev. 1.0
ZyXEL COMMUNICATIONS CORPORATION
i
Limited Warranty
ZyXEL Communications Corporation warrants to the original retail purchaser that
this product is free from defects in materials or workmanship for a period of two (2)
years from the date of purchase. If, during the warranty period, and upon proof of
purchase, the product should have indications of failure due to faulty workmanship
and/or materials, ZyXEL will, at its option, repair or replace the defective products
or components without charge for either parts or labor, and to whatever extent it
shall deem necessary to restore the product or component to proper operating condition. Any replacement will be a new or remanufactured functionally equivalent
product of equal value, and will be solely at the option of ZyXEL. This warranty
shall not apply if the product is modified, misused, tampered with, damaged by
natural causes, or subjected to abnormal working conditions.
NOTE: REPAIR OR REPLACEMENT AS PROVIDED UNDER THIS WARRANTY IS
THE EXCLUSIVE REMEDY OF THE PURCHASER. THIS WARRANTY IS IN LIEU OF
ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING ANY IMPLIED
WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE OR
PURPOSE. ZYXEL COMMUNICATIONS CORPORATION SHALL IN NO EVENT BE
HELD LIABLE FOR INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND OR
CHARACTER TO THE PURCHASER.
To obtain the services of this warranty, please contact ZyXEL SERVICE CENTER
(refer to the separate WARRANTY CARD) for your Return Material Authorization number (RMA). Products must be returned Postage Prepaid. It is recommended that the unit be insured when shipped. Any returned products without
proof of purchase or those with an expired warranty will be repaired or replaced (at
the option of ZyXEL) and the customer will be billed for parts and labor. All
repaired or replaced products will be shipped by ZyXEL to the corresponding
return address, Postage Paid (USA and territories only). If the customer desires
some other return destination beyond the USA borders, the customer shall bear the
cost of the return shipment. This warranty gives you specific legal rights, and you
may also have other rights which vary from state to state and from country to country.
ii
Notice: ZyXEL COMMUNICATIONS CORPORATION does not assume any liability
arising out of the application or use of any products, or software
described herein, neither does it convey any license under its patent
rights nor the patent rights of others. ZyXEL COMMUNICATIONS
CORPORATION further reserves the right to make changes in any
products described herein without notice. This document is subject to
change without notice.
PUBLISHED BY:
ZyXEL COMMUNICATIONS CORPORATION
2F., 58 Park Avenue II
Science-Based Industrial Park
Hsinchu, Taiwan 30077 R.O.C.
EDITED BY:
Computer Software Manuals, Christian Schmitz-Moormann
Wölfelstraße 4, 95444 Bayreuth, Germany
Turtle-Soft EDV-Beratung, D. Katzschke
Hufelandstraße 5, 30453 Hannover, Germany
1995 by ZyXEL Communications Corporation
All rights reserved.
No part of the contents of this publication may be reproduced or transmitted in
any form or by any means without the written permission of the publisher.
iii
Acknowledgments
Trademarks mentioned in this manual are used for plain informational purpose.
Trademarks are properties of their respective owners.
U-Modem, ZFAX and ZyXEL are trademarks of ZyXEL Communications
Corporation.
Smartmodem is a registered trademark of Hayes Microcomputer Products, Inc.
MNP is a registered trademark of Microcom, Inc.
IBM PC, XT, AT and OS/2 are trademarks of I nternational Business M achine Cor-
poration.
Touch-tone is a trademark of American Telephone and Telegraph Corporation.
WINDOWS is a trademark of Microsoft Corporation.
ATARI, ST, STE, MEGA STE, TT, and Falcon030 are trademarks or registered
trademarks of Atari Corporation.
Apple, Macintosh, and Lisa are registered trademarks of Apple Computer Inc.
NeXT, NeXT Cube, and NeXT Station are registered trademarks of NeXT, Inc.
Amiga is a registered trademark of Commodore Business Machines.
.
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FCC Part 15 Information
This device complies with Part 15 of FCC rules. Operation is subject to the following two conditions:
1) This device may not cause harmful interference.
2) This device must accept any interference received, including
interference that may cause undesired operations.
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. However, there is no guarantee that interference will not occur in a particular installation.
If this equipment does cause harmful interference to radio/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 the 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.
Changes or modifications not expressly approved by the party responsible for compliance could void the user's authority to operate the equipment. Shielded RS-232
cables are required to be used to ensure compliance with FCC Part 15, and it is the
responsibility of the user to provide and use shielded RS-232 cables.
FCC REQUIREMENTS
This equipment complies with Part 68 of the FCC Rules. On the base unit of this
equipment is a label that contains, among other information, the FCC Registration
Number and the Ringer Equivalence Number (REN) for this equipment. IF
REQUESTED, THIS INFORMATION MUST BE GIVEN TO THE TELEPHONE COMPANY.
The REN is useful to determine the quantity of the devices you may connect to
your telephone line and still have all of those devices ring when your telephone
number is called. In most, but not all areas, the sum of the REN's of all devices
connected to one line should not exceed five (5.0). To be certain of the number of
devices you may connect to your line, as determined by the total RENs, you should
v
contact your local telephone company to determine the maximum REN for your
calling area.
If your equipment causes harm to the telephone network, the telephone company
may discontinue your service temporarily. If possible, they will notify you in
advance. But if advance notice isn't practical, you will be notified as soon as possible. You will be informed of your right to file a complaint with the FCC.
Your telephone company may make changes in its facilities, equipment, operations,
or procedures that could affect the proper functioning of your equipment. If they
do, you will be notified in advance to give you an opportunity to maintain uninterrupted telephone service.
If you experience trouble with this telephone equipment, please contact the Address
and Phone number listed in the warranty card for information on obtaining service
or repairs.
The telephone company may ask that you disconnect this equipment from the network until the problem has been corrected or until you are sure the equipment is
not malfunctioning.
The user is not authorized to repair or modify the equipment beyond replacing the
EPROMs containing the firmware or uploading firmware into the flash EPROM.
This equipment may not be used on coin service provided by the telephone company. Connection to party lines is subject to state tariffs.
TELEPHONE COMPANY REQUIREMENTS
It is not necessary to notify your telephone company before installing the modem,
but your telephone company may request the following information:
• Telephone number to which the modem is connected.
• Manufacturer and Model Number:
ZyXEL Communications Corporation
Model Name FCC Part 68 Approval Number REN#
You will find this information on the sticker label on the bottom case.
The modem is connected to a public switched line using a USOC (Universal Serv-
ice Order Code) RJ11C modular jack, and to a leased line using a JM8 jack.
vi
Information for Canadian Users
The Industry Canada (IC, formerly DOC) label identifies certified equipment.
This certification means that the equipment meets certain telecommunications network protective, operational, and safety requirements. IC does not guarantee that
the equipment will operate to a user’s satisfaction.
Before installing this equipment, users should ensure that it is permissible to be
connected to the facilities of the local telecommunications company. The equipment must also be installed using an acceptable method of connection. In some
cases, the company's inside wiring associated with a single line individual service
may be extended by means of a certified connector assembly (telephone extension
card). The customer should be awar e that the compliance with the above conditions
may not prevent degradation of service in some situations.
Repairs to certified equipment should be made by an authorized Canadian maintenance facility designated by the supplier. Any r epairs or alterations made by the user
to this equipment, or equipment malfunctions, may give the telecommunications
company cause to request the user to disconnect the equipment.
For their own protection, users should ensure that the electrical ground connections
of the power utility, telephone lines, and internal metallic water pipe system, if
present, are connected together.Tthis precaution may be particularly important in
rural areas.
Caution: Users should not attempt to make such connections themselves, but
should contact the appropriate electrical inspection authority, or electrician, as
appropriate.
The Load Number (LN) assigned to each terminal device denotes the percentage of
the total load to be connected to the telephone loop used by the device without
overloading. The termination on a loop may consist of any combination of devices,
subject only to the requirement that the total of the Load Numbers of all the
devices not exceed 100.
This digital apparatus does not exceed the class B limits for radio noise emissions
from digital apparatus set out in the radio interference regulations of Industry Canada (formerly Canadian DOC).
vii
viii
TABLE OF CONTENTS
FCC Part 15 Information . . . . . . . . . . . . . . . . . . . . . . . . . . v
FCC REQUIREMENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . v
TELEPHONE COMPANY REQUIREMENTS. . . . . . . . . . . . . . . . . . .vi
Information for Canadian Users . . . . . . . . . . . . . . . . . . . . . . vii
BASIC OVERVIEW
INTRODUCTION 1-1
How To Use This Manual. . . . . . . . . . . . . . . . . . . . . . . . .1-2
Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3
The 2864 Series Standard Features . . . . . . . . . . . . . . . . . . . .1-4
Additional specific features . . . . . . . . . . . . . . . . . . . . . . . .1-6
ISDN Ready or Upgradeable . . . . . . . . . . . . . . . . . . . . . . .1-6
Voice Playback and Recording . . . . . . . . . . . . . . . . . . . . . .1-6
Telephony Capability. . . . . . . . . . . . . . . . . . . . . . . . . . .1-6
Parallel and Serial Port Interface . . . . . . . . . . . . . . . . . . . . .1-7
DRAM Expandability . . . . . . . . . . . . . . . . . . . . . . . . . . .1-7
Flash EPROM for Easy Firmware Update. . . . . . . . . . . . . . . . . .1-7
Before You Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-7
How To Become A Registered Owner . . . . . . . . . . . . . . . . . . .1-8
What You Need To Have . . . . . . . . . . . . . . . . . . . . . . . . .1-8
Communication Software. . . . . . . . . . . . . . . . . . . . . . . . .1-8
Connecting To Your Phone . . . . . . . . . . . . . . . . . . . . . . . .1-9
Dial-Up Or Leased Line. . . . . . . . . . . . . . . . . . . . . . . . . .1-9
MODEM AND FAX BASICS 2-1
Modem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-1
DTE and DCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-1
RS-232C or EIA-232D/E . . . . . . . . . . . . . . . . . . . . . . . . .2-1
Serial Port. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-2
Serial RS-232C Cable . . . . . . . . . . . . . . . . . . . . . . . . . .2-2
Synchronous and Asynchronous Communication. . . . . . . . . . . . . .2-2
UART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-2
Modem Standards and Speeds . . . . . . . . . . . . . . . . . . . . . .2-3
Type of Telephone Line. . . . . . . . . . . . . . . . . . . . . . . . . .2-3
Intelligent Modem . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-4
ISDN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-4
AT Command Set . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5
V.25bis Command Set . . . . . . . . . . . . . . . . . . . . . . . . . .2-5
Error Correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5
Data Compression . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-6
TOC-1
MNP Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
V.42bis and V.42 . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Xmodem, Ymodem, and Zmodem. . . . . . . . . . . . . . . . . . . . 2-7
Fax and Facsimile . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Fax Card . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Modem as a Fax . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
EIA Class 1 and Class 2/2.0 Fax Commands . . . . . . . . . . . . . . . 2-8
Autodetection of Fax or Data Call . . . . . . . . . . . . . . . . . . . . 2-8
Caller ID. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Distinctive Ring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Digitized Voice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Cellular Modem . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Automatic Redial / Call Hunting . . . . . . . . . . . . . . . . . . . . . 2-9
Modem Approval and Legal Matters . . . . . . . . . . . . . . . . . . .2-10
MODEM INSTALLATION 3-1
External Modems. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Elite 2864 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Elite 2864 Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Elite 2864 Rear Panel . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Connecting the Elite 2864 . . . . . . . . . . . . . . . . . . . . . . . 3-5
Turning on the Elite 2864. . . . . . . . . . . . . . . . . . . . . . . . 3-6
Elite 2864L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
Elite 2864L Front Panel. . . . . . . . . . . . . . . . . . . . . . . . . 3-7
Elite 2864L Rear Panel . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
Connecting the Elite 2864L . . . . . . . . . . . . . . . . . . . . . . . 3-7
Turning on the Elite 2864L . . . . . . . . . . . . . . . . . . . . . . . 3-7
Elite 2864I and Elite 2864IU . . . . . . . . . . . . . . . . . . . . . . 3-7
Supreme 2864L . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
Supreme 2864L Front Panel . . . . . . . . . . . . . . . . . . . . . . 3-8
Supreme 2864L Rear Panel. . . . . . . . . . . . . . . . . . . . . . . 3-8
Connecting the Supreme 2864L. . . . . . . . . . . . . . . . . . . . . 3-9
Turning on the Supreme 2864L . . . . . . . . . . . . . . . . . . . . . 3-9
Supreme 2864I and 2864IU . . . . . . . . . . . . . . . . . . . . . . 3-9
Omni 288P and Omni 288S . . . . . . . . . . . . . . . . . . . . . .3-10
Omni 288P Front Panel. . . . . . . . . . . . . . . . . . . . . . . . .3-10
Omni 288S Front Panel. . . . . . . . . . . . . . . . . . . . . . . . .3-10
Omni 288P Rear Panel. . . . . . . . . . . . . . . . . . . . . . . . .3-11
Omni 288S Rear Panel . . . . . . . . . . . . . . . . . . . . . . . . .3-12
Connecting the Omni 288P . . . . . . . . . . . . . . . . . . . . . . .3-12
Connecting the Omni 288S . . . . . . . . . . . . . . . . . . . . . . .3-13
Turning on the Omni 288P or Omni 288S . . . . . . . . . . . . . . . .3-13
TOC-2
MODEM OPERATION
MODEM OPERATION 4-1
Parallel or Serial Port Operation. . . . . . . . . . . . . . . . . . . . . .4-1
PC Parallel Port Operation . . . . . . . . . . . . . . . . . . . . . . . .4-2
Parallel Port under Windows . . . . . . . . . . . . . . . . . . . . . . .4-2
Parallel Port under DOS . . . . . . . . . . . . . . . . . . . . . . . . .4-2
Parallel Port Speed Limit . . . . . . . . . . . . . . . . . . . . . . . . .4-2
ZyXEL Parallel Port Adapter. . . . . . . . . . . . . . . . . . . . . . . .4-3
Using the Microphone and Speaker Jacks . . . . . . . . . . . . . . . . .4-3
Non-volatile Memory. . . . . . . . . . . . . . . . . . . . . . . . . . .4-3
Firmware Update/Upgrade . . . . . . . . . . . . . . . . . . . . . . . .4-3
DRAM Upgrade . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-5
Resetting The Modem . . . . . . . . . . . . . . . . . . . . . . . . . .4-5
2864 QUICK START 5-1
LCD Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-1
Panel Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-2
Menu Tree. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-2
LED Status Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-2
Double Arrows on The Screen. . . . . . . . . . . . . . . . . . . . . . .5-3
Dialing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-3
Dial Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-4
Storing a Number . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-4
Dial Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-5
Manual Dial and the DATA/VOICE Switches . . . . . . . . . . . . . . . .5-5
Repeat Last Dial . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-6
Auto Answer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-6
Dialing Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-7
Panel Lock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-9
MODEM PARAMETER SETTINGS 6-1
Parameter Menu. . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-1
Parameter Selection . . . . . . . . . . . . . . . . . . . . . . . . . . .6-2
Status Register Content Modification. . . . . . . . . . . . . . . . . . . .6-2
Menu Tree Elements . . . . . . . . . . . . . . . . . . . . . . . . . . .6-2
TERMINAL OPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . .6-3
MODEM OPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-6
ERROR CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-11
AUDIO OPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12
TOC-3
SETTINGS AND COMMANDS
PROFILES 7-1
Resetting from Profile . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6
Saving to Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-7
Profile Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-7
Resetting Profiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8
STATUS REGISTERS 8-1
Reading and Setting S-Registers . . . . . . . . . . . . . . . . . . . . . 8-1
S-Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . 8-3
ZyXEL-specific Registers. . . . . . . . . . . . . . . . . . . . . . . . . 8-5
AT COMMAND SET SUMMARY 9-1
Basic AT Command Set. . . . . . . . . . . . . . . . . . . . . . . . . 9-1
Extended AT& Command Set . . . . . . . . . . . . . . . . . . . . . . 9-6
Extended AT* Command Set . . . . . . . . . . . . . . . . . . . . . .9-10
SPECIAL FUNCTIONS
ERROR CONTROL AND DATA COMPRESSION 10-1
Error Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-1
Data Compression . . . . . . . . . . . . . . . . . . . . . . . . . . .10-2
Run-length Encoding . . . . . . . . . . . . . . . . . . . . . . . . . .10-3
Adaptive Frequency Encoding . . . . . . . . . . . . . . . . . . . . . .10-3
String Coding . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-3
Bidirectional Compression. . . . . . . . . . . . . . . . . . . . . . . .10-4
Negotiation Fail Fall-Back. . . . . . . . . . . . . . . . . . . . . . . .10-4
DTE to DCE Connection. . . . . . . . . . . . . . . . . . . . . . . . .10-4
Averaging Throughput . . . . . . . . . . . . . . . . . . . . . . . . .10-4
Hints for High-speed Operation . . . . . . . . . . . . . . . . . . . . .10-5
Flow Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-5
Hardware CTS/RTS Flow Control. . . . . . . . . . . . . . . . . . . . .10-5
Software XON/XOFF Flow Control . . . . . . . . . . . . . . . . . . . .10-5
SYNCHRONOUS OPERATION 11-1
Clock Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-1
RTS Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-1
Half-Duplex Operation . . . . . . . . . . . . . . . . . . . . . . . . .11-2
Mode Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-2
Dial from Synchronous Mode . . . . . . . . . . . . . . . . . . . . . .11-2
Auto-answer from Synchronous Mode . . . . . . . . . . . . . . . . . .11-3
Manual Answer from Synchronous Mode. . . . . . . . . . . . . . . . .11-3
Change from Synchronous Mode into Asynchronous Mode . . . . . . . .11-3
Setting up a ZyXEL Modem with the AS-400 . . . . . . . . . . . . . . .11-3
TOC-4
LEASED-LINE OPERATION 12-1
Connecting to a Leased Line . . . . . . . . . . . . . . . . . . . . . . 12-1
Line Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-1
Power Level. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-2
Handshake Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-2
Manual Connection . . . . . . . . . . . . . . . . . . . . . . . . . . 12-2
Auto-handshake . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-2
Leased-Line Dial Backup. . . . . . . . . . . . . . . . . . . . . . . . 12-3
Dial Backup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-3
Aborting from Leased-Line Operation . . . . . . . . . . . . . . . . . . 12-4
Disconnecting a Leased-Line Connection . . . . . . . . . . . . . . . . 12-4
SPECIAL FUNCTIONS 13-1
Security Function . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-1
Remote Configuration . . . . . . . . . . . . . . . . . . . . . . . . . 13-2
Caller Number Delivery(CND). . . . . . . . . . . . . . . . . . . . . . 13-4
Distinctive Ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-5
Extended Distinctive Ring. . . . . . . . . . . . . . . . . . . . . . . . 13-6
Setting Up The EDR . . . . . . . . . . . . . . . . . . . . . . . . . . 13-7
Application Example . . . . . . . . . . . . . . . . . . . . . . . . . . 13-9
V.25bis Command Set . . . . . . . . . . . . . . . . . . . . . . . . . 13-9
CELLULAR MODE OPERATION 14-1
Cellular Phone Systems . . . . . . . . . . . . . . . . . . . . . . . . 14-1
Cellular Impairments. . . . . . . . . . . . . . . . . . . . . . . . . . 14-1
Cellular Modems and ZyCellular Technology. . . . . . . . . . . . . . . 14-2
ZyXEL ZyCellular Modes . . . . . . . . . . . . . . . . . . . . . . . . 14-3
Cellular Mode Usage. . . . . . . . . . . . . . . . . . . . . . . . . . 14-3
Cellular Modem Installation. . . . . . . . . . . . . . . . . . . . . . . 14-4
FAX OPERATION 15-1
ITU-T T.30 Fax Protocol . . . . . . . . . . . . . . . . . . . . . . . . 15-1
Fax Command Sets . . . . . . . . . . . . . . . . . . . . . . . . . . 15-2
Class 1 Command Set . . . . . . . . . . . . . . . . . . . . . . . . . 15-2
Class 2 Command Set . . . . . . . . . . . . . . . . . . . . . . . . . 15-3
Extended Fax AT Commands . . . . . . . . . . . . . . . . . . . . . 15-13
Flow Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-16
Parallel Receiving with the Fax Machine. . . . . . . . . . . . . . . . 15-17
Fax reception from within a BBS System. . . . . . . . . . . . . . . . 15-17
Direct FAX Reception and Printing. . . . . . . . . . . . . . . . . . . 15-18
Stand-alone FAX Reception and Storing . . . . . . . . . . . . . . . . 15-20
TOC-5
ADVANCED VOICE CAPABILITY 16-1
Voice Data Compression . . . . . . . . . . . . . . . . . . . . . . . .16-1
Automatic Detection of Voice, Fax and Data . . . . . . . . . . . . . . .16-2
Voice States and Operation Modes. . . . . . . . . . . . . . . . . . . .16-2
Voice Command State . . . . . . . . . . . . . . . . . . . . . . . . .16-3
Voice Data State . . . . . . . . . . . . . . . . . . . . . . . . . . . .16-4
Voice Data Transmission State. . . . . . . . . . . . . . . . . . . . . .16-4
Voice Data Receival State . . . . . . . . . . . . . . . . . . . . . . . .16-4
Events and Actions with Shielded Code. . . . . . . . . . . . . . . . . .16-5
Event Detection and Reporting. . . . . . . . . . . . . . . . . . . . . .16-5
Action Commands in Voice Data State . . . . . . . . . . . . . . . . . .16-7
Voice AT Commands . . . . . . . . . . . . . . . . . . . . . . . . . .16-8
Supported Commands For Voice Mode Operation . . . . . . . . . . . . .16-9
Action Voice Commands for Voice Mode Operation . . . . . . . . . . . 16-12
Configuration Commands for Voice Mode Operation. . . . . . . . . . . 16-14
Examples of Voice Mode Operation . . . . . . . . . . . . . . . . . . 16-20
Connecting a Telephone Set to the Modem's PHONE Jack . . . . . . . . . 16-27
NETWORK MANAGEMENT CAPABILITY 17-1
ZyXEL Modem Network Management System . . . . . . . . . . . . . . .17-1
Hierarchical Modem Network . . . . . . . . . . . . . . . . . . . . . .17-1
Distributed Management . . . . . . . . . . . . . . . . . . . . . . . .17-1
NMS Capable Models. . . . . . . . . . . . . . . . . . . . . . . . . .17-2
DIAGNOSTICS 18-1
Power-on Self-test . . . . . . . . . . . . . . . . . . . . . . . . . . .18-1
Analog Loopback Test (AT&T1) . . . . . . . . . . . . . . . . . . . . .18-2
Analog Loopback with Self-test (AT&T8) . . . . . . . . . . . . . . . . .18-3
Local Digital Loopback Test (AT&T3) . . . . . . . . . . . . . . . . . .18-3
Remote Digital Loopback Test (AT&T6) . . . . . . . . . . . . . . . . .18-4
Remote Digital Loopback with Self-test (AT&T7) . . . . . . . . . . . . .18-4
Line Condition Status Display . . . . . . . . . . . . . . . . . . . . . .18-5
Link Status Report (ATI2) . . . . . . . . . . . . . . . . . . . . . . . .18-7
Throughput Display. . . . . . . . . . . . . . . . . . . . . . . . . . 18-10
Retransmission Indicator . . . . . . . . . . . . . . . . . . . . . . . 18-10
Dialing Indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-10
Handshaking And Retrain Indicator . . . . . . . . . . . . . . . . . . 18-10
Firmware Update . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-10
TOC-6
HINTS AND TIPS
GENERAL HINTS AND TIPS 19-1
Activating Saved Settings upon Turning-on. . . . . . . . . . . . . . . . 19-1
Avoiding Low Throughput and Loss of Data . . . . . . . . . . . . . . . 19-1
Disabling Compression May Yield Faster Transfers . . . . . . . . . . . . 19-1
Avoiding Disconnections during a Handshake on a Leased Line . . . . . . . 19-1
Avoiding Disconnections when Making a Data Call. . . . . . . . . . . . 19-1
Calling from an Extension / Blind Dial. . . . . . . . . . . . . . . . . . 19-2
THE FIRST CONNECTION 20-1
ZyXEL MODEMS AND A PC 21-1
Serial Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-1
Parallel Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-2
Using the Windows 3.1 Terminal Program. . . . . . . . . . . . . . . . 21-2
Hardware Hints . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-2
ZyXEL Serial/Parallel I/O Adapter Card. . . . . . . . . . . . . . . . . . 21-3
ZyXEL MODEMS AND UNIX 22-1
Hints for Unix Setups. . . . . . . . . . . . . . . . . . . . . . . . . . 22-1
Cable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-1
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-1
Software Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-2
ZyXEL MODEMS AND APPLE MACINTOSH 23-1
Connector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-1
Apple Macintosh Particularities . . . . . . . . . . . . . . . . . . . . . 23-1
Cable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-2
Software for the Apple Macintosh . . . . . . . . . . . . . . . . . . . . 23-3
ZyXEL MODEMS AND ATARIS 24-1
Cable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-1
Hardware Tips. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-2
Software Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-2
ZyXEL MODEMS AND AMIGA 25-1
Cable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-1
Software Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-2
Hardware Tips. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-2
TOC-7
APPENDICES
GLOSSARY GLO-1
EIA-232D INTERFACE A-1
PHONE JACK PIN ASSIGNMENTS B-1
ZyXEL PARALLEL PORT INTERFACE C-1
V.25bis COMMAND SET D-1
STANDARDS E-1
ASCII Control Characters . . . . . . . . . . . . . . . . . . . . . . . . E-1
Selection of ITU-T standards. . . . . . . . . . . . . . . . . . . . . . . E-2
Data transmission through telephone networks (V.1 -V.110). . . . . . . . E-3
INDEX Index-1
TOC-8
Chapter 1
INTRODUCTION
The 2864 series of V.34 modems includes three sub-series of models, namely the Supreme, Elite and Omni series. The Supreme and Elite series models have ISDN capability or can be upgraded to have ISDN capability . The Omni series does not have
ISDN capability . The Supreme series provides an LCD display panel while the Elite
series has a front panel with LED indicators only. Many features are common to all
three series. If not noted otherwise, a feature illustrated with one series model in this
manual applies to the other models and series as well.
The Elite 2864 series of high-speed modems features four base 10models. They differ only in the implemented line interface module, everything else is equivalent except for the panel LED indicator designations.
The models are
Model Name
Elite 2864 Dial-up line DAA Dial-up analog PSTN line
Elite 2864L Dial-up and leased line
Elite 2864I ISDN S-interface ISDN line, S-interface
Elite 2864IU ISDN U-interface ISDN line, U-interface
The Elite 2864 has a 2-wire dial-up line DAA (Direct Access Arrangement) module
for connection to a normal PSTN (Public Switched Telephone Network) 2-wire
dial-up phone line. The Elite 2864L has a DAA with both a dial-up and leased line
interface. A 2 or a 4-wire leased line can also be used besides the normal 2-wire dialup line. Dial back-up capability is provided while using leased line. The Elite 2864I
has an ISDN S-interface module that will connect to an ISDN S-interface line. It
will connect to an ISDN call or a modem/fax call from PSTN made to this ISDN
line. A U-interface ISDN module is available for the USA market. The Elite 2864IU
is the ISDN model with the U-interface module.
By changing the line interface module, one Elite model will essentially become another Elite model. Each Elite model has different markings on its front and rear panels. Thus, in addition to the line interface module the front and rear panel also need
to be changed in order to transform one Elite model into a different Elite model.
Note that each Elite model has its own telecommunication authority approval
Line Interface Module Phone Line Used
Dial-up and/or 2/4-wire leased ana-
DAA
log line
1–1
number. When the model is changed, the approval number is also changed. F ind the
new approval number and check whether it is appropriate for the user to do the
model transformation before you start the transformation process.
Like the Elite series, the Supreme series includes different models which differ only
in the line interface module. There are three models in the Supreme series - The Supreme 2864L, 2864I, and 2864IU. The S upreme 2864L has a DAA with both a dialup and leased-line interface; the Supreme 2864I has an ISDN S-interface module;
the Supreme 2864IU has an ISDN U-interface module.
The Omni series models have only modem/fax/voice capability . They do not pro vide
ISDN capability nor are they ISDN upgradeable. The Omni 288P is the model with
a parallel port DTE interface and the Omni 288S is with a serial port DTE interface.
The Supreme and Elite models have both a parallel port and a serial port DTE interface.
How To Use This Manual
This manual describes the use of all models in the 2864 series and gives instruction
for their installation and operation. The 2864I and 2864IU ISDN models come
with a separate manual describing their ISDN operation.
The manual is divided into five sections.
Basic Overview - The first section is comprised of chapter 1 (INTRODUCTION)
through chapter 3 (MODEM INSTALLATION). It gives a basic overview of the
2864 series modems' features, introduces some basics of modem operation for novice users, and explains the installation of the different models of the 2864 series.
Modem Operation - The second section introduces you to some skills you will need
to make the best use of your modem. In chapter 4 (MODEM OPERATION) you are
introduced to the use of the different modem ports and you will find information
on how to return the modem to standard settings (reset) and how to upgrade your
modem in the future. The panel operation of the Supreme models is described in
chapter 5 (2864 QUICK START) and chapter 6 (MODEM PARAMETER SETTINGS). Users of the non-LCD models should consult the equivalent A T command
sections listed for each of the panel operations.
Settings and Commands - The third section, chapter 7 (PROFILES) through
chapter 9 (AT COMMAND SET SUMMARY), provides an overview of the settings
and commands which are available in the 2864 series.
Special Functions - Section four is comprised of chapter 10 (ERROR CONTROL
AND DATA COMPRESSION) through chapter 18 (DIAGNOSTICS) and describes
many special functions of the 2864 series modems in detail, including data compression, synchronous and leased-line operation, remote configuration, caller ID, cellu-
1–2
lar mode, fax sending and receiving, voice mail, network management, and
diagnostic features.
Hints and T ips - Section five is the trouble-shooting and special advice section. Here
you will find additional information on how to use a 2864 series modem with your
computer, and some hints and tips r elating to a number of communication software
applications.
Appendices - An extensive glossary, several appendices with technical details, information on standards, and a thorough index complete this manual.
Those who need more detailed technical information may contact ZyXEL Communications Corporation directly . The address can be found in the disclaimer section at
the beginning of this manual.
Compatibility
ZyXEL 2864 series modems are high performance universal modems capable of
transmission speeds up to 28.8 Kbps full-duplex on a 2-wire dial-up line. Universal
compatibility covers a broad range of ITU-T and BELL standards, and provides data
compression.
Various operation modes that can be achieved are as follows:
Standard
Bit rate
(+/-0,01%)
[bps]
Baud rate
(+/-0,01%)
[baud]
Modulation Carrier
frequency
[Hz]
V .34 28 800 - 2 400 multiple multiple multiple
ZyXEL 19 200 2 743
ZyXEL 16 800 2 400
V.33
V.33
*
*
14 400 2 400 128-TCM 1800
12 000 2 400 64-TCM 1800
V.32bis 14 400 2 400 128-TCM 1800
V.32bis 12 000 2 400 64-TCM 1800
V.32bis 7 200 2 400 16-TCM 1800
V.32 9 600 2 400 32-TCM 1800
V.32 uncoded 9 600 2 400 16-QAM 1800
V.32 4 800 2 400 4-DPSK 1800
*
V.29
*
V.29
*
V.29
V.27bis
*
9 600 2 400 16-QAM 1700
7 200 2 400 8-QAM 1700
4 800 2 400 4-DPSK 1700
4 800 1 600 8-PSK 1800
1–3
Standard
V .27bis
V.26bis
*
*
Bit rate
(+/-0,01%)
[bps]
Baud rate
(+/-0,01%)
[baud]
Modulation Carrier
frequency
[Hz]
2 400 1 200 4-DPSK 1800
2 400 1 200 4-DPSK 1800
V.23 1200 / 75 1200 / 75 FSK
V.23 600 / 75 600 / 75 FSK
†
V.22bis
2 400 600 16-QAM 1200 Orig.
2400 Ans.
†
V.22
(BELL 212A)
1 200 600 4-DPSK 1200 Orig.
2400 Ans.
V.21 300 300 FSK
BELL 103 300 300 FSK
G3 FAX implemented according to T.30, V.17,V.29 and V.27ter.
Cellular Modes ZyXEL proprietary cellular modes; 14400 bps to 4800 bps.
*. V33, V.29, V.27bis and V.26bis are only available in model 2864L for 4-wire
leased-line operation. The other operation modes are common to all models.
V.26bis works in half-duplex mode on 2-wire dial-up line.
†. 1800 Hz guard tone for V.22bis/V .22 answer mode, 6 dB below data signal level.
The 2864 Series Standard Features
• Synchronous/Asynchronous operations for external stand alone models and
rack mount models. (Parallel port interface is for asynchronous transmission
only)
• Asynchronous operations for PC internal card model.
• MNP class 4/5 error correction/data compression.
• V.42/V.42bis error correction/data compression. V.42 with selective reject.
• Extended AT command set.
• V.25bis async/sync command set.
• Operation on 2-wire dial-up line or 2/4-wire leased line. (4-wire leased line on
2864L only.)
• Auto-dial/answer and manual originate/answer.
• Tone/Pulse dialing.
• Dial tone, busy signal, and ringback detection.
• Programmable speaker volume control.
1–4
• Non-volatile memory for parameter/setting storage.
• Remote configuration.
• Security call back.
• Caller ID detection.
• Distinctive ring detection.
• Extensive status reports.
• Diagnostics available for:
• Modem full self-test
• Analog loopback (with self-test)
• Remote digital loopback (with self-test)
• Digital loopback
• XON/XOFF software and CTS/RTS hardware flow control.
• Line status monitoring available for (only Supreme 2864):
• Signal-to-noise ratio
• Received signal level
• Frequency offset
• Phase jitter
• Retrain granted
• Retrain requested
• Round trip echo delay
• Carrier loss counter
• Rate change granted.
• Rate change requested
• Blocks retransmitted
• Blocks received in error
• 20×2 LCD and directional keypads. (Supreme 2864 only)
• G3 Fax sending and receiving capability with speeds up to 14400 bps.
• Fax-Polling / Fax-Grouping.
• Automatic detection of data or fax call.
• Digitized voice capability with speech compression.
• DTMF tone detection.
• Special cellular modes for data communication through cellular link.
1–5
Additional specific features
ISDN Ready or Upgradeable
The 2864I model has an ISDN module to connect to an ISDN line. On the other
2864 models the phone line interface module may be removed and replaced instead
by an ISDN module to become an ISDN modem. The ISDN modem has both
ISDN capability and normal modem/fax/voice capability.
For ISDN capability, the 2864I supports a 2B+D ISDN basic rate interface. On the
B channel, the 2864I supports one B channel at 64Kbps or two B channels bundled
at 128Kbps. With data compression, the throughput is up to a few hundred Kbps.
The 2864I also supports one B channel for data and the other B channel for voice
communication. On the D channel, the 2864I supports 1TR6 protocol for German
ISDN, DSS1 protocol for Euro ISDN and NI1, AT&T 5ESS and Northern Telecom DMS-100 for North America ISDN.
A full feature analog port (a/b adapter) is provided. Thus, a r egular telephone equipment may be connected to the ISDN line to make and receive ISDN calls through
this port. The metering pulse is also supported on this analog port for countries supporting it.
For modem/fax/voice capability, the 2864I can initiate and receive modem/fax calls
to/from a modem or fax machine connected to a PSTN analog telephone line. V oice
mail capability is also supported for voice calls to/from an ISDN or analog PSTN
line.
Voice Playback and Recording
A normal telephone set may be connected to the phone jack of the modem for local
voice message playback or recording. The modem provides the necessary DC voltage
and current for the telephone set to operate.
A microphone and a speaker jack are also provided for voice recording or playback.
An external microphone, speakers or a headset may be connected to the modem
through these jacks.
A large and good quality internal speaker is installed to provide better sound for
voice and music playback.
Telephony Capability
The 2864 series modem can detect the on/off-hook status or polarity change of the
phone line connection and the attached telephone set. These will be reported as
events in voice mode to the connected computer. The modem can also control and
switch between telephone connecting to line and modem connecting to line. It can
1–6
also control the switching between the phone line connecting to the modem and the
telephone set connecting to the modem. Both the modem and the telephone set may
also be connected to the line at the same time. A telephony software program can
utilize these capabilities to support various telephony functions.
Parallel and Serial Port Interface
The Supreme and Elite models have both a serial port and a parallel port. The Omni
model has either a serial or a parallel port. The serial port has a speed up to
460.8Kbps with auto speed detection (AT autobaud). The parallel port can connect
to either a PC's parallel port or a printer's parallel port. When it is connected to a
bidirectional PC parallel port, the PC can communicate with the modem through
the parallel port. The parallel port connection has the advantage that no data loss due
to overrun will occur and there is no serial port speed limit. When the modem's parallel port is connected to a laser printer with a Centronics type interface (the normal
PC to printer parallel interface), the modem can send received fax pages directly to
the printer without the need to start up a PC.
DRAM Expandability
8 Mbyte DRAM expandability is standard on the Supreme and Elite series modems.
Four DRAM sockets are provided on board to accept four 4M×4 16M DRAM
chips. The DRAM memory is useful for overnight stand-alone fax receiving. A bout
200 pages of normal fax can be stored without overflowing the DRAM memory . The
stored fax pages are available for later retrieval or printing.
Flash EPROM for Easy Firmware Update
With the versatile and feature rich hardware architecture, the 2864 series modems
are ready for firmware updates/upgrades for added and enhanced features. An 8
Mbit high-speed flash EPROM is standard on every 2864 modem (4 Mbit on Omni
models). A firmware update is only an A T command to upload a new firmware file.
It is not necessary to open the case or burn any EPROM.
Before You Start
Before you proceed further, please check the modem package and make sur e nothing
is missing. The complete package should include:
1–7
• one (1) 2864 series universal modem
• one (1) power adapter (external model)
• one (1) RJ11 telephone cable
• one (1) JM8 leased-line cable (2864L model only)
one (1) RJ45 ISDN telephone cable (2864I model only)
• one (1) 2864 series user’s manual
• one (1) ZFAX 3.5" floppy disk and floppy disk(s) for drivers and other utilities.
• one (1) warranty/registration card
• one (1) Quick Reference Card
Contact your dealer or the store where you bought the modem if anything is missing. Check the modem for shipping damages. If you find any damage, contact the
shipping agency immediately.
Retain the shipping and cushioning materials for future storage or shipping needs.
Please direct any additional questions about damaged or missing materials to your
dealer or distributor, or to the factory address listed on your warranty card.
How To Become A Registered Owner
Fill in the registration card and mail it to the address found on the r everse side of the
card. Registered owners will receive future product and update information. You
don't have to register to receive warranty service. A dated invoice as proof of purchase along with the warranty card are sufficient.
What You Need To Have
You must provide the following additional equipment to operate your modem:
• A Computer/Terminal with communication software.
• A RS-232 serial cable or a 25-wire DB25 parallel cable (with one male and one
female connector).
• A telephone line from your telephone company (dial-up or leased line).
Communication Software
Communication software controls the modem connected to the computer and directs data to and from the modem. In most PC environments, the modem is used in
an asynchronous mode and the software controls the modem by AT commands.
1–8
ZyXEL modems support the extended AT command set and are compatible with
most communication software packages. However , there are some unique features in
the ZyXEL modem and there are a few unique commands to control them.
Some communication packages need a file with information about the commands
and features the modem supports. Basic information on how to set up communication software can be found in chapter 20 (THE FIRST CONNECTION). Information and sample data files for popular communication software packages are
available in the Application Driver Area of the ZyXEL BBS (+886-35-787045).
Connecting To Your Phone
If you would like to use a single phone line for voice and modem connections, remove your phone cable from the RJ11 junction box and plug one end of the RJ11
cable (supplied with the modem) into the phone junction box on the wall, then plug
the other end of the cable into the rear panel of the modem labeled DIAL-UP LINE
or WALL. Finish by plugging your phone cable into the r ear panel of the modem labeled PHONE. Please refer to the illustrations in chapter 3 (MODEM INSTALLA-
TION).
Dial-Up Or Leased Line
The 2864 and Omni 288 models may connect to 2-wire dial-up or leased lines only .
The 2864L offers you a choice of connecting to 2-wire dial-up lines (more commonly known as public lines) and 2/4-wire leased lines. To use the 2864L on a leased line,
you must order and install a USOC JM8 jack. You must also specify 4-wire operation without TEK leads for the wiring option. When setting up a pair of modems
for leased line point-to-point operation, one modem must be configured for originate mode and the other for answer mode. Both RJ11C and JM8 cables are supplied
for your convenience.
1–9
1–10
Chapter 2
MODEM AND FAX BASICS
This chapter is intended for those readers who want to know the details behind modem and fax operations; what's going on behind the scenes. In addition to introducing basic modem and fax terminology , this chapter helps users to understand and be
able to utilize the available features. Experienced modem and fax users may wish to
skip this chapter.
Modem
Modem is a compound word of MOdulator and DEModulator. A modem is used
for computer communications. Refer to Fig. 2.1 for a standard modem setup and
application.
Modem
Fig. 2.1: Modems are used in computer communications.
A modem translates computer data to analog signals (modulation) that can travel
through the telephone network and reach another modem. The remote modem
translates the analog signal received back into data (demodulation) and sends the information to the receiving-end computer. Modems are telephones for computers,
what they use to talk to each other.
Modem
DTE and DCE
DTE and DCE are terminologies used in data communication. DTE stands for
Data Terminal Equipment and DCE stands for Data Circuit terminating Equipment (Data Communication Equipment). Referring to Fig. 2.1, the computer or
terminal is the DTE and the modem is the DCE.
2–1
RS-232C or EIA-232D/E
RS-232C is the Recommended Standard (RS) of the Electronic Industries Association (EIA), defining the serial communication interface between a DTE and a DCE.
The 232 is basically a serial number for the defined standard. Sometimes it is necessary to redefine a standard, or to revise it. The most commonly used r evision of the
RS-232 standard is the "C" revision. For the "D" revision, the pr efix was changed to
EIA. Except for a few added, but not commonly used signals, there is no practical
difference between the "C" and "D" revisions. Ther e is now a new revision with the
”E“ suffix. The RS-232C standard is equivalent to the ITU-T V.24 and V.28 standard. Also refer to the Modem Standards and Speeds section below.
Serial Port
A serial port is the serial data connector together with its internal circuit on the DTE
or DCE with electrical and mechanical characteristics according to RS-232C. Since
some signals are going from the DTE port to DCE port, and some signals are going
in the other direction, the signal pin is a transmitter on one port and a receiver on
the other. The DTE serial port is different from the DCE serial port in terms of signals on the connector pins. There are also mechanical differences in terms of male
(with pins) or female (with holes) connectors.
Serial RS-232C Cable
A serial RS-232C cable is used to connect a DTE port to a DCE port. Do not use a
null-modem cable (which may be used to connect two DTEs directly with each other through their serial ports). A normal RS-232C connector has 25 pins and a normal RS-232C cable has 25 wires. Many signals in the RS-232C are not used in
common applications and a 9-wire RS-232C cable is sufficient in most applications.
The PC-A T's serial port has only 9 connector pins, eliminating the unnecessary pins.
For high-speed DTE-DCE comunication, use a low-capacitance cable, as short as
possible.
Synchronous and Asynchronous Communication
There are two kinds of serial data communication. One is called synchronous and
the other is called asynchronous. In synchronous communication, data is transmitted and received bit by bit and is timed by an accompanying clock signal. In asynchronous communication, data is sent character by character (or octet by octet), and
the idle time between characters is variable. No clock signal is sent; character timing
is recovered from the data itself.
2–2
A PC's COM1 and COM2 are asynchronous serial ports. Most PCs' and Unix systems' serial data communications are asynchronous. The serial data communication
on an IBM mainframe or mini is synchronous.
UART
A UART (Universal Asynchronous Receiver Transmitter) is the device used in a DTE
or DCE for asynchronous data reception and transmission. The standar d UAR T device used in PCs is of the NS16450 type. For high-speed serial data transfers (38400
bps and up), the PC may not serve the UART fast enough and data may get lost. In
this case, a UART with data buffer is needed, such as the NS16550A type device.
Modem Standards and Speeds
The ITU-T or ITU-TSS (International Telecommunications Union - Telecommunications Standardization Sector), is the international standard-making body for telecommunications. They draft recommendations. The recommendations they make
for modem applications have a "V" prefix and are called V-series recommendations.
The commonly used ITU-T modem standards for 2-wire dial-up line are:
Standard
V.34 28 800 - 2 400
V.32bis 14 400 / 12 000 / 7 200
V.32 9 600 / 4 800
*
V.22bis
V.22 1 200
V.21 300
V.23 1 200 / 75
*. bis is the old French word for second.
In the USA, Bell Systems used to create de facto standards such as Bell 212A for
1200 bps modems and Bell 103 for 300 bps modems. Everyone follows the ITU-T
standards now for newer and higher-speed modems.
ZyXEL 2864 series modems support all the above mentioned modem standards and
are compatible with existing modems.
Speed (bps)
2 400 / 1 200
Type of Telephone Line
The commonly used phone service is a 2-wire dial-up line. There are only two wires
connecting the modem to the phone company's central office. The same two wires
are used for DC current feeding, ringing, dialing, on/off-hook monitoring, and sig-
2–3
nal transmission in both directions. This is the type of phone service most people
have in their home or office. Since the same two wires are used for both transmitting
and receiving signals, an echo of the transmitting signal will also be received and it
is the modem receiver's task to remove the echo before demodulation.
Leased-line phone service is also available from phone companies in a 4-wire form.
Here, both the transmitting and receiving signals each use a separate 2-wire pair and
thus no echo problem will result. Normally, no DC current feeding, ringing, or dialing function is provided on a leased line.
There is also the 2-wire leased line which is a permanent 2-wire connection.
Intelligent Modem
Formerly, modem functions, settings, and operations were simple and everything
was controlled by manual switches, either internal or external, or by wire-strapping
settings. No computer control was provided.
All of an intelligent modem’s functions, including dialing and answering, are controllable by the computer or terminal it is connected to by means of the same RS-232
serial interface used for data connection.
An intelligent modem operates in one of two states - the command state or the data
state. In command state, the modem interprets data received from the serial interface
as commands and sends back an action result in response. In data state, the modem
modulates the data received from the serial interface and sends the demodulated data
to the serial interface as received data. The user needs to know whether the modem
is in the command state or data state and how to switch it.
ISDN
The normal telephone network PSTN (Public Switched Telephone Network) transmits voice band analog signals from end to end. A modem is needed at each end to
transmit digital data. The digital telephone network ISDN (Integrated S ervices Digital Network) transmits digital data from end to end, thus no modem is needed to
transmit data. Instead, an ISDN telephone is needed at each end to translate voice
signals to and from digital data for ISDN digitized voice data transmission.
ISDN TA
ISDN has a digital interface at the customer site. An ISDN TA (T erminal A dapter)
will adapt the user terminal’s interface, usually an asynchronous or synchronous serial interface, to the ISDN digital interface, usually the S- or T-interface. With an
ISDN TA a user connects a computer/terminal to the ISDN telephone line in the
same way as he/she uses a modem to connect a computer/terminal to the PSTN telephone line.
2–4
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