ZyXEL Communications U-1496 series User manual

ZyXEL
U-1496 Series Modems
User’s Manual
Copyright 1994-1997 by ZyXEL Communications Corp.

Chapter One - INTRODUCTION
THE U-1496 SERIES UNIVERSAL MODEMS
The U-1496 series of high-speed modems feature five base models.
They are:
U-1496
External stand alone model with 20 x 2 LCD display and menu
control.
Also called U-1496S. Includes 2/4-wire leased line support.
U-1496E
External stand alone model with LED status indicators. 2-wire
application only.
U-1496B
PC internal card version.
U-1496R
Rack mount modem card version. Up to 16
U-1496Rs can be housed in
a RS-1600 rack with central panel control and 20 x 4 LCD display.
U-1496P
A portable model, particularly suitable for cellular data
communications.
There are also models with a plus (+) suffix, such as U-1496E+,
U-1496R+, and U-1496B+. These plus versions have a faster
processor and more memory space to support the ZyXEL 19200 bps
high-speed mode, advanced voice capability, and future updates
with more enhanced features.
The basic features, functions, and operation of the plus versions
are the same as those of the normal version. We do not
specifically mention the plus version in this manual unless there
are functional or operational differences. The U-1496 LCD model
is always a plus version.
HOW TO USE THIS MANUAL
This manual describes the use of all models in the U-1496 series,
the U-1496, U-1496E, U-1496B, U-1496P, and U-1496R. Usually, this
manual describes the operation of the U-1496, the model with the
largest set of functions. If a description does not apply to a
certain model, you may skip the description.
The manual is structured into roughly 5 sections.
The first section comprises chapters 1 through 3. It gives a

basic overview of the U-1496 series modems' features, introduces
some basics of modem operation for novice users, and explains the
installation of the different models of the U-1496 series
including the U-1496B PC-card. Please note that the COM port and
interrupt number must be properly chosen, before the U-1496B can
be installed.
The panel operation of the U-1496 is described in Chapter 4 and
5. The U-1496 has an LCD display menu control panel. The rack
system has a central menu control panel similar to that of the
U-1496. Users of the other models should consult the equivalent
AT command sections listed for each of the panel operations.
The third section, chapters 6 through 8, provides an overview
of the settings and commands which are available in the U-1496
series.
Section four comprises chapters 9 through 17 and describes many
special functions of the U-1496 series modems in detail,
including data compression, synchronous and lease line operation,
remote configuration, caller ID, cellular mode, fax send and
receive, voice mail, network management, and diagnostic features.
Section five is the trouble-shooting and special advice section.
Here you find additional information on how to use a U-1496
series modem with your computer, and some hints and tips
relating to a number of communication software applications.
A glossary, several appendices with technical details and
information on standards, and a thorough index complete this
manual.
The RS-1600 rack system comes with a supplemental User's Guide
describing the use and installation of the rack system. The
Network Management System comes with a separate manual detailing
its installation and usage.
Compatibility
ZyXEL U-1496 series modems are high performance universal
modems capable of transmission speeds up to 19.2 Kbps full-duplex
on a 2-wire dial-up line. Universal compatibility covers a broad
range of CCITT and BELL standards, and provides data compression
and error free transmission.
Various operation modes that can be achieved are as follows:
Bit rate Baud rate Modulation Carrier
(+/-0.01%) (+/-0.01%) Freq
bps baud Hz
ZyX19200 19,200 2743 256TCM 1800
ZyX16800 16,800 2400 256TCM 1800
V.33 14,400 2400 128-TCM 1800

V.33 12,000 2400 64-TCM 1800
V.32bis 14,400 2400 128-TCM 1800
V.32bis 12,000 2400 64-TCM 1800
V.32bis 7,200 2400 16-TCM 1800
V.32 9,600 2400 32-TCM 1800
V.32 uncoded 9,600 2400 16-QAM 1800
V.32 4,800 2400 4-DPSK 1800
V.29 9,600 2400 16-QAM 1700
V.29 7,200 2400 8-QAM 1700
V.29 4,800 2400 4-DPSK 1700
V.27ter 4800 1600 8-PSK 1800
V.27ter 2400 1200 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
2400 bps speed range.
1800 Hz guard tone for V.22bis/V.22 answer mode, 6 dB below
data signal level.
Note: V.33, V.29, V.27bis, V.27ter and V.26bis are only available in
models U-1496 and U-1496R for 4-wire leased line operation. The
other operation modes are common to all models.
THE U-1496 SERIES STANDARD FEATURES
Synchronous/Asynchronous operations for external stand alone
models and rack mount model.
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 feature.
Extended AT command set.
V.25bis async/sync command set.
Operate on 2-wire dial-up line or 2/4-wire leased line. (4-wire
leased line on U-1496 and U-1496R only.)
Auto-dial/answer and manual originate/answer.
Tone/Pulse dialing.
Dial tone, busy, and ringback detection.

Programmable speaker volume control.
Non-volatile memory storage.
Remote configuration.
Security call back.
Caller ID detection.
Distinctive ring detection.
Extensive Status reports.
Diagnostics available for:
Modem full self test
Analog loopback (w/ self test)
Remote digital loopback (w/ self test)
Digital loopback
XON/XOFF or CTS/RTS flow control.
Line status monitoring available for: (U-1496 and U-1496R)
Signal-to-noise ratio
Receive 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 in error
20 X 2 LCD display and directional keypads. (On U-1496 model
only, 20 x 4 on rack panel.)
G3 Fax send and receive capability with speeds up to 14400 bps.
Fax-Polling / Fax-Grouping.
Automatic detection of data or fax call.
Digitized voice capability with speech compression.
Special cellular modes for data communications through cellular
link.
Full two-year warranty.

BEFORE YOU GET STARTED
Before you proceed further, please check to see if you have all
the necessary materials from the shipping package and make sure
nothing is missing. The complete package should include:
one (1) U-1496 series universal modem
one (1) power adapter pack (stand alone model only)
one (1) RJ11 telephone cable
one (1) JM8 leased line cable (U-1496 only)
one (1) U-1496 series user's manual
one (1) ZFAX 3.5" floppy disk
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. After you unpack the modem,
please check for shipping damages. If you find any damage,
contact the shipping agency immediately.
Please retain the shipping carton 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 factory with
address listed on your warranty card.
HOW TO BECOME A REGISTERED OWNER
Simply fill in the registration card and mail it to the address
found on the reverse 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 need the following equipment to operate your modem:
Computer/Terminal with communication software (e.g,. PC with
Windows Terminal).
RS-232 serial cable (not supplied with modem).
Note: If you bought the internal PC card, you don't need a serial
cable.
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. For most cases
in the PC environment, the modem is used in an asynchronous mode
and the software controls the modem by the AT commands. 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 "modem data file" to tell it which commands and features
the modem supports. The floppy disk included with your modem
package features sample data files for some popular communication
software packages.
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 modem) into
the socket on the phone, then plug the other end of the cable to
the rear panel of the modem labeled "DIAL-UP LINE" or "WALL".
Finish by plugging in your phone cable to the rear panel of the
modem labeled "PHONE". Please refer to the illustration in Fig.
3-3.
DIAL-UP OR LEASED LINE
The U-1496E and U-1496B can connect to 2-wire dial-up or leased
lines only. The U-1496 and U-1496R offer you a choice of
connecting to 2-wire dial-up line (more commonly known as public
lines) and 2/4-wire leased lines. To use the U-1496 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 must be configured for originate mode and the
other for answer mode. Both RJ11C and JM8 cables are supplied for
your convenience.
Chapter Two - MODEM AND FAX BASICS
This chapter is intended for those who want to know the details behind modem and fax
operations; what's going on behind the scenes. In addition to basic modem and fax terminology,
this chapter helps users understand and use the available features. Experienced modem and
fax users may wish to skip this chapter.
WHAT IS A 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. A modem translates computer
data to analog signals (modulation) that can travel through the

telephone network and reach the other 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.
((*MODE-02*; Modem as used in computer communications))
WHAT ARE 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.
WHAT IS RS-232C OR EIA-232D
RS-232C is the Recommended Standard (RS) by the Electronic
Industries Association (EIA) defining the serial communication
interface between a DTE and a DCE. The most commonly used
revision is the "C" revision. For "D" revision, it changes the
prefix to EIA. Except for a few added, but not commonly used
signals, there is no practical difference between the "C" and "D"
revisions. RS-232C is equivalent to CCITT V.24 and V.28.
WHAT IS A 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 or female connectors.
SERIAL RS-232C CABLE
A serial RS-232C cable is used to connect a DTE port to a DCE
port. 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-AT's serial port has only 9 connector
pins, eliminating the unnecessary pins.
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), the idle time between characters is variable. No clock

signal is sent; character timing is recovered from the data
itself.
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.
WHAT IS UART
UART (Universal Asynchronous Receiver Transmitter) is the device
used in a DTE or DCE for asynchronous data reception and
transmission. The normal UART device used in PCs is of the
NS16450 type. For high-speed serial data receiving (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.
MODEM STANDARDS AND SPEEDS
The CCITT (Comite International Telegraphique et Telephonique, now called
ITU-TSS (International Telecommunications Union - Technical Standardization Sector), is the
international standard-making body for telecommunication. They draft "recommendations". The
recommendations they made for modem applications have a "V" prefix and are called V-series
recommendations. The commonly used CCITT standards for 2-wire dial-up line are:
V.32bis 14400/12000/7200 bps
V.32 9600/4800 bps
V.22bis 2400 bps
V.22 1200 bps
V.21 300 bps
V.23 1200/75 bps
Note: bis is the French word for second.
In the USA, Bell Systems used to create the de facto standard
such as Bell 212A for 1200 bps modems and Bell 103 for 300 bps
modems. Everyone is following the CCITT standard now for newer
and higher speed modems.
ZyXEL U-1496 series modems support all the above mentioned modem
standards and are compatible with existing modems.
TYPE OF TELEPHONE LINE
The commonly used phone service is a 2-wire dial-up line. Only
two wires connect 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 signal 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.

A leased-line phone service is also available from phone companies in a 4-wire form. Here the
transmitting and receiving signal each uses 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 case of a 2-wire leased line which is a
permanent 2-wire connection.
INTELLIGENT MODEM
In the old days, 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.
An intelligent modem has all its functions, including dialing and
answering, controllable by the computer or terminal it is
connected to, through the same RS-232 serial interface used for
data connection.
An intelligent modem operates in one of two states - the command
state and the data state. In command state, the modem interprets
data received from the serial interface as "commands" and send
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.
AT COMMAND SET
The AT command set is the industry de facto standard used to
control a modem in command state. It got its name from the fact
that every command line has a prefix "AT".
AT commands were first used in the Hayes Smartmodem (R) and hence
adopted by other modem manufacturers and communication software
writers. The original set of AT commands such as dialing,
answering, etc., is used by everyone else and is standardized.
The AT command set is extended by each modem manufacturer for
control of ever-increasing modem functions and capabilities. This
"extended" or "enhanced" command set is not standardized
whatsoever.
The AT command set is used only with an asynchronous serial data
interface.
ZyXEL has defined a set of extended AT commands to support many
of its unique functions and features.
V.25bis COMMAND SET
V.25bis is a set of auto-dialing commands defined by the CCITT.
V.25bis supports both synchronous and asynchronous data