ZyXEL Communications 56K Plus User Manual

Omni 56K Plus Series

DATA/FAX Modem

User’s Guide

Version 1.0.0

July 2004

Omni 56K Plus Series User’s Guide

Copyright

The contents of this publication may not be reproduced in any part or as a whole, transcribed, stored in a retrieval system, translated into any language, or transmitted in any form or by any means, electronic, mechanical, magnetic, optical, chemical, photocopying, manual, or otherwise, without the prior written permission of ZyXEL Communications Corporation.

Disclaimer

ZyXEL 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 further reserves the right to make changes in any products described herein without notice.

This publication is subject to change without notice.

Trademarks

Trademarks mentioned in this publication are used for identification purposes only and may be properties of their respective owners.

ii Copyright

Omni 56K Plus Series User’s Guide

Federal Communications Commission (FCC)

Interference Statement

This device complies with Part 15 of FCC rules. Operation is subject to the following two conditions:

This device may not cause harmful interference.

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 commercial environment. 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.

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.

Notice 1

Changes or modifications not expressly approved by the party responsible for compliance could void the user's authority to operate the equipment.

Certifications

1. Go to www.zyxel.com.

2. Select your product from the drop-down list box on the ZyXEL home page to go to that product's page.

3. Select the certification you wish to view from this page.

FCC Statement iii

Omni 56K Plus Series User’s Guide

ZyXEL Limited Warranty

ZyXEL warrants to the original end user (purchaser) that this product is free from any defects in materials or workmanship for a period of up to two years from the date of purchase. During the warranty period, and upon proof of purchase, should the product have indications of failure due to faulty workmanship and/or materials, ZyXEL will, at its discretion, 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 components to proper operating condition. Any replacement will consist of a new or re-manufactured functionally equivalent product of equal value, and will be solely at the discretion of ZyXEL. This warranty shall not apply if the product is modified, misused, tampered with, damaged by an act of God, 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 shall in no event be held liable for indirect or consequential damages of any kind of character to the purchaser.

To obtain the services of this warranty, contact ZyXEL's Service Center 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 outdated warranty will be repaired or replaced (at the discretion 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. This warranty gives you specific legal rights, and you may also have other rights that vary from country to country.

Online Registration

iv ZyXEL Limited Warranty

Omni 56K Plus Series User’s Guide

Customer Support

When you contact your customer support representative please have the following information ready:

Please have the following information ready when you contact customer support.

• Product model and serial number.

• Warranty Information.

• Date that you received your device.

• Brief description of the problem and the steps you took to solve it.

REGULAR MAIL

LOCATION

WORLDWIDE

AMERICA

SUPPORT E-MAIL TELEPHONE1 WEB SITE METHOD

SALES E-MAIL FAX1 FTP SITE

support@zyxel.com.tw +886-3-578-3942 www.zyxel.com

sales@zyxel.com.tw

support@zyxel.com +1-800-255-4101

sales@zyxel.com

support@zyxel.de +49-2405-6909-0 www.zyxel.de GERMANY

sales@zyxel.de

support@zyxel.es +34 902 195 420 SPAIN

sales@zyxel.es

support@zyxel.dk +45 39 55 07 00 www.zyxel.dk DENMARK

sales@zyxel.dk

support@zyxel.no +47 22 80 61 80 www.zyxel.no NORWAY

sales@zyxel.no

support@zyxel.se +46 31 744 7700 www.zyxel.se SWEDEN

sales@zyxel.se

support@zyxel.fi +358-9-4780-8411 www.zyxel.fi FINLAND

sales@zyxel.fi

+886-3-578-2439 ftp.europe.zyxel.com

+1-714-632-0882

+1-714-632-0858 ftp.us.zyxel.com

+49-2405-6909-99

+33 (0)4 72 52 97 97 FRANCE info@zyxel.fr

+33 (0)4 72 52 19 20

+34 913 005 345

+45 39 55 07 07

+47 22 80 61 81

+46 31 744 7701

+358-9-4780 8448

www.europe.zyxel.com

ftp.zyxel.com

www.us.zyxel.com NORTH

www.zyxel.fr ZyXEL France

www.zyxel.es

ZyXEL Communications

ZyXEL Communications Corp. 6 Innovation Road II Science Park Hsinchu 300 Taiwan

ZyXEL Communications Inc. 1130 N. Miller St. Anaheim CA 92806-2001 U.S.A.

ZyXEL Deutschland GmbH. Adenauerstr. 20/A2 D-52146 Wuerselen Germany

1 rue des Vergers Bat. 1 / C 69760 Limonest France

Alejandro Villegas 33 1º, 28043 Madrid Spain

ZyXEL Communications A/S Columbusvej 5 2860 Soeborg Denmark

ZyXEL Communications A/S Nils Hansens vei 13 0667 Oslo Norway

ZyXEL Communications A/S Sjöporten 4, 41764 Göteborg Sweden

ZyXEL Communications Oy Malminkaari 10 00700 Helsinki Finland

“+” is the (prefix) number you enter to make an international telephone call.

Customer Support v

Omni 56K Plus Series User’s Guide

Copyright................................................................................................................................................ii

Federal Communications Commission (FCC) Interference Statement .......................................... iii

ZyXEL Limited Warranty ...................................................................................................................iv

Customer Support..................................................................................................................................v

Table of Contents ..................................................................................................................................vi

List of Tables ........................................................................................................................................vii

Preface................................................................................................................................................. viii

Chapter 1 Introduction.................................................................................................................. 1-1

1.1 ZyXEL Omni 56K Plus modem Overview ........................................................................ 1-1

1.2 Main Features ..................................................................................................................... 1-1

Chapter 2 Specifications and Function Description ................................................................... 2-1

2.1 Hardware Specifications..................................................................................................... 2-1

2.2 Firmware Specifications..................................................................................................... 2-1

2.3 Protocol Support................................................................................................................. 2-2

2.4 Capability ........................................................................................................................... 2-3

2.5 Data Function ..................................................................................................................... 2-4

2.6 Fax function...................................................................................................................... 2-10

2.7 Voice Function ................................................................................................................. 2-10

Chapter 3 Result Codes ................................................................................................................. 3-1

Chapter 4 Command Sets.............................................................................................................. 4-1

4.1 Data command sets............................................................................................................. 4-1

4.2 Fax command sets .............................................................................................................. 4-8

4.3 Voice AT Commands ....................................................................................................... 4-16

4.4 Voice Shielded DTE Commands...................................................................................... 4-18

4.5 Voice Shielded DTE Responses ....................................................................................... 4-18

4.6 S-Register Descriptions .................................................................................................... 4-19

Chapter 5 Firmware Upgrade ......................................................................................................5-1

5.1 Upgrading by Utility........................................................................................................... 5-1

5.2 Upgrading by Terminal Emulation Program ...................................................................... 5-2

Index.........................................................................................................................................................i

vi Table of Content

Omni 56K Plus Series User’s Guide

List of Tables

Table 2-1 Hardware Specification ........................................................................................................2-1

Table 2-2 Firmware Specification ........................................................................................................2-1

Table 2-3 Feature Description ..............................................................................................................2-4

Table 2-4 Physical Layer Capacity.......................................................................................................2-4

Table 2-5 Different Ring Types in Register S40 ..................................................................................2-8

Table 2-6 Fax Physical Layer Capacity..............................................................................................2-10

Table 3-1 Result Codes.........................................................................................................................3-1

Table 4-1 Basic AT Command Sets .....................................................................................................4-1

Table 4-2 AT Command Sets Requiring an "AT" Prefix .....................................................................4-1

Table 4-3 Extended AT& Command Sets ............................................................................................4-3

Table 4-4 Extended AT* Command Sets .............................................................................................4-6

Table 4-5 Extended AT# Command Sets .............................................................................................4-8

Table 4-6 Service Class 1 Commands ..................................................................................................4-8

Table 4-7 The Value of <MOD> Parameters .......................................................................................4-8

Table 4-8 Command Syntax .................................................................................................................4-9

Table 4-9 Supported Commands (per TIA PN2388 8/20/90)...............................................................4-9

Table 4-10 Class 2 Command Responses...........................................................................................4-12

Table 4-11 Service Class 2.0 Commands ...........................................................................................4-13

Table 4-12 Voice AT Commands.......................................................................................................4-16

Table 4-13 Voice Shielded DTE Commands .....................................................................................4-18

Table 4-14 Voice Shielded DTE Responses.......................................................................................4-18

Table 4-15 Basic S-Registers "ATSn=x"............................................................................................4-19

Table 4-16 Extended S-Registers "ATSn=x" .....................................................................................4-19

List of Tables vii

Omni 56K Plus Series User’s Guide

Preface

About This User's Manual

Congratulations on your purchase of the ZyXEL Omni 56K USB Plus or Omni 56K COM Plus modem.

This manual is designed to provide general information for Omni 56K USB Plus and Omni 56K COM Plus modems and advanced information for technical users who might need them for programming or other applications.

This manual may refer to the Omni 56K USB Plus and/or Omni 56K COM Plus modems as the Omni 56K Plus.

Introduction

This chapter introduces you to the features and specifications for the ZyXEL Omni 56K USB

Plus and Omni 56K COM Plus modems.

1.1 ZyXEL Omni 56K Plus modem Overview

The Omni 56K USB Plus or Omni 56K COM Plus is an analog Data/Fax modem used for Internet access via PSTN line. Models included in this series at the time of writing are the Omni 56K COM Plus and the Omni 56K USB Plus. The difference between these two models is: the Omni 56K COM Plus uses RS-232 Com port interface and the Omni 56K USB Plus uses Universal Serial Bus (USB) connection to a computer. Users can connect the cables without turning off the computer which makes it simple to install the modem. It can run upstream and downstream maximum rates of 56Kbps. The rate selection depends on the line quality, and server side configuration.

1.2 Main Features

 ZyXEL fifth generation data pump with V.92 capability.

 V.92 56K up/down-stream data transmission.

 Fast retrain with auto fall-forward and fall-back.

 Automatic Data/Fax call detection.

 G3 14.4Kbps Fax send/receive.

 Support Fax class 1, class 2 and class 2.0 command set.

 Handset voice record and play.

 Voice digitization and compression.

 Voice record via IS101 Command Set

 Error correction & data compression.

 Microsoft 95/98//98SEMe/2000/XP Windows plug and play compatible (Omni 56K COM

Plus only).

 Microsoft 98SE/Me/2000/XP Windows USB plug and play compatible (Omni 56K USB

Plus only).

 Flash EPROM upgradeable.

Introduction 1-1

Omni 56K Plus Series User’s Guide

Chapter 2

Specifications and Function

Description

This chapter introduces the specifications and functions of the Omni 56K Plus. This chapter

and the next three chapters are designed for advanced users who might need more

information about the Omni 56K Plus modem's specifications and functions when

programming or other applications.

2.1 Hardware Specifications

Table 2-1 Hardware Specification

ITEM SPECIFICATION DESCRIPTION

Power Requirements 9V AC (Omni 56K COM Plus only)

Operating Requirements

Weight Omni 56K COM Plus: 194.6 g

Dimensions

Temperature: 0° C to 40° C

Humidity: 20 to 90 % (non-condensing)

Omni 56K USB Plus: 170.4 g

112.5 mm (W) x 29 mm (H) x 106 mm (L)

2.2 Firmware Specifications

Table 2-2 Firmware Specification

Physical layer for data mode

Multi-Auto

V.92

V.90

V.34bis 33.6 Kbps to 2.4 Kbps

V.34 28.8 Kbps to 2.4 Kbps

V.32bis 14.4/12/9.6/7.2/4.8 Kbps

V.32 9.6/4.8 Kbps

V.23 1200/600/75 bps

V.22bis 2.4 Kbps

V.22/Bell 212A 1.2K bps

V.21/Bell 103 300 bps

Auto Fallback/Forward

Specifications and Function Description 2-1

Omni 56K Plus Series User’s Guide

Table 2-2 Firmware Specification

Link layer

Flow Control

Command set

Diagnostics

Fax

Voice

MNP 3-4

MNP 5

V42

V42bis

V.44

Hardware flow control: RTS/CTS

Software flow control: XON/XOFF

Full AT command set

Dialing type: DTMF/Pulse

Power-on self-test

Analog loop-back test

Analog loop-back with self-test

Local digital loop-back test

Remote digital loop-back test

Remote digital loop-back with self-test

V.17 FAX (send and receive)

V.29 G3 FAX (send and receive)

V.27ter G3 FAX (send and receive)

EIA Class 1 Command SetEIA Class 2 Command Set

EIA Class 2.0 Command Set

4 bits / sample ADPCM,9600 samples / second.

On-line voice playback and recording.

IS-101 voice command set.

2.3 Protocol Support

 Data Physical Layer

 ITU-T V.92

 ITU-T V.90

 ITU-T V.34bis/V.34

 ITU-T V.32bis/V.32

 ITU-T V.22bis/V.22

 ITU-T V.21

 ITU-T V.23

 Bell 212A

 Bell 103

 Fax Physical Layer

2-2 Specifications and Function Description

Omni 56K Plus Series User’s Guide

 ITU-T V.17

 ITU-T V.29

 ITU-T V.27ter

 ITU-T V.21

 Error Control and Data Compression

 ITU-T V.44

 ITU-T V.42

 ITU-T V.42bis

 MNP3-5

 Command Set

 Standard command set

 EIA Class 1 Fax Command set

 EIA Class 2 Fax Command set

 EIA Class 2.0 Fax Command set

 Basic AT Command set

 ZyXEL AT Command set

 Extended AT& Command Set

 Extended AT* Command Set

 Extended AT# Command Set

 IS101 Voice Command set

For more information on detailed command sets, please refer to Chapter 4.

2.4 Capability

The data/fax/voice feature of the Omni 56K Plus is described as below.

Specifications and Function Description 2-3

Omni 56K Plus Series User’s Guide

Table 2-3 Feature Description

FEATURE DESCRIPTION

Data 2W Dial-Up Line

Multi-auto/ V.92/V.90/V.34/V.32bis/V.32/V.22bis/V.22/V.21/Bell 103

Hardware/Software Flow Control

Error Control/Data Compression

ZyXEL AT Command Set

External Plug and Play for Windows 95/98/98SE/Me/2000/XP in RS232 mode

External Plug and Play for Windows 98SE/Me/2000/XP in USB mode

Repeat Dial/Cyclic Dial

Caller ID

Distinctive Ring

AT Protection for software application

Fax V.17/V.29/V.27ter

G3 T.30 Protocol

EIA Class 1/Class 2/Class 2.0 command set

Voice 4 bit IMA ADPCM

Remote Recording on PC storage

Play and record voice via the attached telephone set.

IS-101 Command Set

2.5 Data Function

2.5.1 Physical Layer Capability

The Omni 56K Plus is a high performance universal modem capable of transmission speed up to 56/48 Kbps full-duplex on a 2-wire dial-up line. Universal compatibility covers a broad range of ITU-T and BELL standards.

Table 2-4 Physical Layer Capacity

STANDARD BIT RATE [BPS] BAUD RATE [BAUD] MODULATION CARRIER FREQUENCY [HZ]

V.90 28000-56000 8000 PCM 0

V.92 (upstream)

V.92 (downstream)

V.34bis/V.34 2400-33600 multiple TCM multiple

V.32bis 14400 2400 128-TCM 1800

V.32bis 12000 2400 64-TCM 1800

V.32bis 7200 2400 16-TCM 1800

V.32 9600 2400 32-TCM 1800

24000-48000 8000 PCM 0

24000-56000 8000 PCM 0

2-4 Specifications and Function Description

Omni 56K Plus Series User’s Guide

Table 2-4 Physical Layer Capacity

STANDARD BIT RATE [BPS] BAUD RATE [BAUD] MODULATION CARRIER FREQUENCY [HZ]

V.32 uncoded 9600 2400 16-QAM 1800

V.32 4800 2400 4-DPSK 1800

V.23 1200/75 1200/75 FSK

V.23 600/75 600/75 FSK

V.22bis 2400 600 16-QAM 1200 Call

2400 Ans

V.22

(BELL 212A)

V.21 300 300 FSK

BELL 103 300 300 FSK

1200 600 4-DPSK 1200 Call

2400 Ans

2.5.2 Flow Control

This feature refers to stopping and restarting the flow of data into and out of the modem’s transmission and receiving data buffers. Flow control is necessary so that a device does not receive more data than it can handle. The Omni 56K Plus provide two kinds of flow control methods.

2.5.3 Hardware CTS/RTS Flow Control

This is a bi-directional flow control where CTS and RTS are RS-232 signals which must be available on your computer. When the modem’s transmission buffer is almost full, the modem will drop CTS to signal the DTE that it cannot accept data any more. Turn on the CTS to notify the DTE that it can keep sending data to the modem. On the computer software side, when the receiving buffer of the software is almost full, it will drop RTS to signal the modem to stop sending data to the DTE. Turn on the RTS and the modem will start sending data again to the DTE.

2.5.4 Software XON/XOFF Flow Control

This is a bi-directional flow control. XON and XOFF character defaults are decimals 17 and 19.These can be changed by modifying the S-Registers S31 and S32.Both the modem and the DTE will treat XOFF as a signal to stop transmitting data and will treat XON as a signal to restart sending data. Modems will not send these characters received from the local DTE to the remote modem.

2.5.5 Error Control

Error control keeps the modem data link error-free by detecting and re-transmitting erroneous data. The Omni 56K Plus modems support both MNP and V.42 error control protocols. The MNP protocol was an industry standard developed and licensed by Microcom, Inc. Omni 56K Plus modems support level 4 and 3 error control protocols, commonly denoted as MNP4 and MNP3.

V42 is a developed standard by CCITT. V.42 supports both LAPM and MNP4. A V.42 handshaking will try an LAPM connection first, and if not successful, it will try MNP4. The maximum data block size used in the Omni 56K Plus modem is 256 bytes.

Specifications and Function Description 2-5

Omni 56K Plus Series User’s Guide

2.5.6 Data Compression

In the modem, the data compression is activated in an attempt to reduce the number of bits actually sent. The receiving modem applies these techniques in reverse to recover the actual data from the compressed data stream.

Omni 56K Plus modems support V.44, V.42bis and MNP5 data compression protocols. Data compression needs an error-free data link to work correctly, otherwise the corrupted compressed data stream will ruin the decompression process. MNP5 is used with MNP4 error control. V.44 and V.42bis is used with V.42 error control. The compression efficiency of V.42bis is generally higher than that of MNP5. In some cases, V.42bis can be 50 % to 100% higher and in other cases it is just slightly higher. In general, it is about 50 % more efficient.

2.5.7 Repeat Dial

The modem will dial the default number stored in non-volatile RAM, EEPROM , repeatedly if not connected.(s38.0=1,*Dn)

2.5.8 Cyclic Dial

Dial the number stored in EEPROM at location n(0-3) if cyclic dial s44.3=1 is set.

If the first dial is not successful, the modem will cycle dial through the four numbers stored in memory.

2.5.9 Caller Number Delivery (Caller ID)

Caller Number Delivery (CND), commonly called Caller ID, is a new kind of phone service that may be offered by your local phone company. Check your phone company for availability. You must subscribe to it and usually pay an additional monthly service charge for this service.

With CND service, the phone company's central office will send the coded caller information to the called station. This information is sent once between the first and second ring. Your modem can decode this caller information and present it to the connected computer/terminal during the second ring period as part of the call progress ring message. The modem will also report the Caller ID information if asked by the command AT*T.

There are two kinds of caller information message formats sent by the phone company.

One is the single message format which includes date, time, and caller ID

The other is the multiple message format which also includes the caller name as registered with the phone company.

The command ATS40.2=n is used to enable (n=1) or disable (n=0) the Caller ID detection function. The default is disabled. Enable it only when you have this service and want to enable its detection.

 The Caller ID message may cause some communication

software that is not expecting it to become confused. If you plan to use the Caller ID feature, be sure you are using software that supports it.

In single message format, the modem will send a ring message to the terminal as follows:

RING

2-6 Specifications and Function Description

Omni 56K Plus Series User’s Guide

TIME: <MM-DD hh:mm>

CALLER NUMBER: <CALLER_ID> or CALLER NAME:<CALLER_NM>

RING

MM is the two-digit month message, DD is the two-digit date message, hh is the hour and mm is the minute of the time, and CALLER_ID is the phone number of the caller or CALLER_NM his/her name.

The following is an example of a caller ID message as it might appear on your screen:

RING

TIME: 04-28 12:30

CALLER NUMBER: 7135551414 or CALLER NAME: Brent Harper

RING

In the multiple message format, if the caller's number and name are available, the ring message will display both:

RING

TIME: MM-DD hh:mm

CALLER NUMBER: <Caller_ID>

CALLER NAME: <Caller_Name>

RING

Here is an example:

RING

TIME: 04-28 12:30

CALLER NUMBER: 7135551414

CALLER NAME: Tracy Huang

RING

If the caller number and name are not available, the ring message will appear as follows:

RING

TIME: 04-28 12:30

REASON FOR NO NUMBER: OUT_OF_AREA

REASON FOR NO NAME: PRIVACY

RING

The last CND message that the modem received can be displayed by using the AT*T command.

Specifications and Function Description 2-7

Omni 56K Plus Series User’s Guide

Setting S48.0=1 will cause the modem to report CND information in its ASCII coded hexadecimal raw data format. The DTE software is responsible for explaining the data.

 Please refer to the Bellcore Technical Advisory document TR-

NWT-000030 for the exact data format. The above Caller ID scheme applies to the North America area. Different countries may employ different Caller ID schemes, check if the scheme used in your country is supported before using the Caller ID feature. For most other Caller ID schemes, only the Caller telephone number is provided.

2.5.10 Distinctive Ring

Distinctive Ring is a phone service that may be offered by your phone company. Check your phone company for availability. With this service, you can have several phone numbers assigned to the same phone line. The phone company will send a different type of ring signal for each phone number being called. The subscriber can distinguish which number is called by which type of ring is received.

One benefit of this feature is the ability to have three numbers on the same line allowing you to list the three numbers for voice, data, and fax, respectively. You can then have your fax machine answer only the ring corresponding to the fax number and have your modem answer only the ring corresponding to the data number. A voice call will not be answered by either fax machine or data modem and it will only be answered when someone picks up the phone. You can also have the answering machine answer only the voice ring. A more complicated use is that you can have one number for multiple uses, such as one number for both data and fax.

A ring signal is a composition of repeated on and off states. Different types of rings usually correspond to different compositions of the ”on” part (cadence) of the ring. Your modem can distinguish up to four types of ring signals and can be commanded to answer or not answer any one of these four types of ring signals. Following is a list of these four types of ring signals. These are the ring types used in the USA. The difference among the ring types is the two-second ON part of the ring signal. It comprises a long, double short, or triple short ring.

S-register S40 bits 3-6 are used for distinctive ring control. Each bit controls the answering of a particular ring type. Setting a bit to “1” enables answering, setting it to “0” rejects the ring. Note that the ring may still be heard even if it is not counted as an accepted ring by the modem.

The control relationships between bits 3-6 in register S40 and the different ring types are:

Table 2-5 Different Ring Types in Register S40

TYPE BIT (ON) RING SEQUENCE

1.2s or 2s on; 4s off

0.8s on, 0.4s off, 0.8s on; 4s off

0.4s on, 0.2s off, 0.4s on, 0.2s off, 0.8s on; 4s off

0.3s on, 0.2s off, 1s on, 0.2s off, 0.3s on; 4s off

2.5.11 Security Function

The Omni 56K Plus modem provides a security function, that (when enabled) prevents an unauthorized user from making a connection. Two types of security function are provided. Type 1

2-8 Specifications and Function Description

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