ZyXEL Communications 56K Plus Series 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
ii Copyright
Copyright
Copyright © 2004 by ZyXEL Communications Corporation.
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.
Published by ZyXEL Communications Corporation. All rights reserved.
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.

Omni 56K Plus Series User’s Guide
FCC Statement iii
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.

Omni 56K Plus Series User’s Guide
iv ZyXEL Limited Warranty
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 out-
dated 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
Register online registration at www.zyxel.com for free future product updates and information.

Omni 56K Plus Series User’s Guide
Customer Support v
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.
SUPPORT E-MAIL TELEPHONE1WEB SITEMETHOD
LOCATION
SALES E-MAIL FAX1FTP SITE
REGULAR MAIL
[email protected]m.tw [phone] www.zyxel.com
www.europe.zyxel.com
ftp.zyxel.com
WORLDWIDE
[e-mail] [phone] ftp.europe.zyxel.com
ZyXEL Communications Corp.
6 Innovation Road II
Science Park
Hsinchu 300
Taiwan
[email protected]m [phone]
[phone]
www.us.zyxel.comNORTH
AMERICA
[e-mail] [phone] ftp.us.zyxel.com
ZyXEL Communications Inc.
1130 N. Miller St.
Anaheim
CA 92806-2001
U.S.A.
[email protected] [phone] www.zyxel.deGERMANY
[e-mail] [phone]
ZyXEL Deutschland GmbH.
Adenauerstr. 20/A2 D-52146
Wuerselen
Germany
[phone]FRANCE [email protected]
[phone]
www.zyxel.fr ZyXEL France
1 rue des Vergers
Bat. 1 / C
69760 Limonest
France
[email protected] [phone]SPAIN
[e-mail] [phone]
www.zyxel.es ZyXEL Communications
Alejandro Villegas 33
1º, 28043 Madrid
Spain
[email protected] [phone] www.zyxel.dkDENMARK
[e-mail] [phone]
ZyXEL Communications A/S
Columbusvej 5
2860 Soeborg
Denmark
[email protected] [phone] www.zyxel.noNORWAY
[e-mail] [phone]
ZyXEL Communications A/S
Nils Hansens vei 13
0667 Oslo
Norway
[email protected] [phone] www.zyxel.seSWEDEN
[e-mail] [phone]
ZyXEL Communications A/S
Sjöporten 4, 41764 Göteborg
Sweden
[email protected] [phone] www.zyxel.fiFINLAND
[e-mail] [phone]
ZyXEL Communications Oy
Malminkaari 10
00700 Helsinki
Finland
1“+” is the (prefix) number you enter to make an international telephone call.

Omni 56K Plus Series User’s Guide
vi Table of Content
Table of Contents
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

Omni 56K Plus Series User’s Guide
List of Tables vii
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

Omni 56K Plus Series User’s Guide
viii Preface
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.
Related Documentation
 Support Disk
Refer to the included CD for support documents.
 Quick Start Guide
The Quick Start Guide is designed to help you quickly learn how to install your Omni 56K
USB Plus or Omni 56K COM Plus modem.
 Packing List Card
The Packing List Card lists all items that should have come in the package.
 Certifications
Refer to the product page at www.zyxel.com for information on product certifications.
 ZyXEL Glossary and Web Site
Please refer to www.zyxel.com for an online glossary of networking terms and additional
support documentation.
User’s Guide Feedback
Help us help you. E-mail all User’s Guide-related comments, questions or suggestions for
improvement to [email protected] or send regular mail to The Technical Writing Team,
ZyXEL Communications Corp., 6 Innovation Road II, Science-Based Industrial Park, Hsinchu, 300,
Taiwan. Thank you.
Syntax Conventions
• The version number on the title page is the latest firmware version that is documented in this
User’s Guide. Earlier versions may also be included.
• “Enter” means for you to type one or more characters and press the carriage return. “Select” or
“Choose” means for you to use one of the predefined choices.
• The SMT menu titles and labels are in Bold Times New Roman font. Command and arrow keys
are enclosed in square brackets. [ENTER] means the Enter, or carriage return key; [ESC] means
the Escape key and [SPACE BAR] means the Space Bar.
• The choices of a menu item are in Bold Arial font.

Omni 56K Plus Series User’s Guide
Preface ix
• Mouse action sequences are denoted using a comma. For example, “click the Apple icon, Control
Panels and then Modem” means first click the Apple icon, then point your mouse pointer to
Control Panels and then click Modem.
• For brevity’s sake, we will use “e.g.” as a shorthand for “for instance” and “i.e.” for “that is” or
“in other words” throughout this manual.

Omni 56K Plus Series User’s Guide
Introduction 1-1
Chapter 1
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.

Omni 56K Plus Series User’s Guide
Specifications and Function Description 2-1
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 Temperature: 0°C to 40°C
Humidity: 20 to 90 % (non-condensing)
Weight Omni 56K COM Plus: 194.6 g
Omni 56K USB Plus: 170.4 g
Dimensions 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

Omni 56K Plus Series User’s Guide
2-2 Specifications and Function Description
Table 2-2 Firmware Specification
Link layer MNP 3-4
MNP 5
V42
V42bis
V.44
Flow Control Hardware flow control: RTS/CTS
Software flow control: XON/XOFF
Command set Full AT command set
Dialing type: DTMF/Pulse
Diagnostics 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
Fax 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
Voice 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

Omni 56K Plus Series User’s Guide
Specifications and Function Description 2-3
 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.

Omni 56K Plus Series User’s Guide
2-4 Specifications and Function Description
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)
24000-48000 8000 PCM 0
V.92
(downstream)
24000-56000 8000 PCM 0
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

Omni 56K Plus Series User’s Guide
Specifications and Function Description 2-5
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)
1200 600 4-DPSK 1200 Call
2400 Ans
V.21 300 300 FSK
BELL 103 300 300 FSK
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.

Omni 56K Plus Series User’s Guide
2-6 Specifications and Function Description
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

Omni 56K Plus Series User’s Guide
Specifications and Function Description 2-7
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.

Omni 56K Plus Series User’s Guide
2-8 Specifications and Function Description
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
2
3
4
3
4
5
6
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