ZyXEL Communications U-336S, U-336SA User Manual

4 (1)

U-336S and U-336SA

User’s Manual

Version 3.0



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 (2) 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 remanufactured 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 or character to the purchaser.

To obtain the services of this warranty, please contact ZyXEL’s 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 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 (USA and territories only). If the customer


desires some other return destination beyond the U.S. 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.

Copyright © 1999 by ZyXEL

The contents of this book may not be reproduced (in any part or as a whole) or transmitted in any form or by any means without the written permission of the publisher.

Published by ZyXEL Communications Corporation. All rights reserved.

Note: 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 patents rights of others. ZyXEL further reserves the right to make changes in any products described herein without notice. This document is subject to change without notice.


Trademarks mentioned in this manual are used for informational purposes only.

Trademarks are properties of their respective owners.

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 A 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.

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.

Information for Canadian Users

The Industry Canada label identifies certified equipment. This certification means that the equipment meets certain telecommunications network protective, operation, and safety requirements. The Industry Canada 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. The customer should be aware 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 repairs 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. This 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.

This digital apparatus does not exceed the class A limits for radio noise emissions from digital apparatus set out in the radio interference regulations of Industry Canada.

The declarations of CE marking:

Note: This applies only for U-336S model.


This product has been approved for connection to the Public Switched Telecommunication Network using interfaces compatible with ITU-TSS recommendation I.420 (Basic Rate ISDN user access). This product complies with the following directives:

1.The Council Directive 89/336/EEC of 3 May 1992 on the approximation of the laws of the member states relation to Electro Magnetic Compatibility. (EMC Directive)

2.Council Directive 91/263/EEC of 29 April 1991 on the approximation of the laws of the Member States concerning telecommunication terminal equipment. (The Telecom Terminal Equipment Directive)

3.93/68/EEC of 22 July 1993 amending the Directives 89/336/EEC, 91/263 /EEC and 92/31/EEC.(Marking Directive)

The Council Directive 92/31/EEC of 28 April 1992 amending directive on the approximation of the laws of the member states relating to EletoMagnetic Compatibility.

Contacting ZyXEL

If you have questions about your ZyXEL product or desire assistance, contact ZyXEL Communications Corporation in one of the following ways:

Phone: In North America call between 8:00 AM and 5:00 PM PST at (714) 693-0808

Outside North America, you can dial +886-3-5783942 between 8:00AM and 5:00PM Taiwan time (GMT +8:00).

Fax: ZyXEL in North America: (714) 693-8811 or Taiwan: +886- 3-5782439



Sales inquiries: sales@zyxel.com in North America sales@zyxel.com.tw outside North America.

Technical support: support@zyxel.com in North America. support@zyxel.com.tw outside North America.

Product information: Visit our site on the World Wide Web: http://www.zyxel.com.

FTP: Information , such as ZyXEL software and ROM updates for North America can be found at this FTP address: ftp.zyxel.com

For European versions and related files, use the address: ftp.zyxel.co.at

Postal Service: You can send written communications at the following address:

ZyXEL Communications Corporation

6, Innovation Road II, Science-Based Industrial Park Hsinchu, Taiwan 300, R.O.C.


ZyXEL Communications Inc. 1650 Miraloma Avenue Placentia, CA92870, U.S.A.




ZyXEL Limited Warranty ii

FCC Part 15 Information iii

Information for Canadian Users iv

Contacting ZyXEL vi

1 Introduction 1

Required Equipment 1

Modem Features 2

Standard Features 2

Intelligent Features 3

Fax Compatibility 4

Technical Specifications 4

2 Installation 7

Front Panel 7

Front Panel LEDs 8

Front Panel Switches 9

Rear Panel Markings 9

Modem Connection 10

Powering Up 12

3 Basic Modem Operation 13

Understanding AT Commands 13

Using the Windows 95 Hyper Terminal Program 14

Dialing and Answering Techniques 15

Dialing using the ATD Command 15


Auto-Answer and Hook Controls 16

Quick Tips when issuing AT Commands 17

Modem Result Codes 19 Viewing S Register Values 19 Changing S Register Values 20

Non-Volatile Memory 20

Storing Phone Numbers 21 Dialing Stored Phone Numbers 21

Saving Settings and User Profiles 21

Helpful Hints for PC Computers 22

Default Modem Settings for PC’s 23 ZyXEL Serial/Parallel I/O Card 23

Helpful Hints for Mac Computers 24

Special AT Command Settings for Mac 24 Mac Serial Port 24

Mac Software Tips 24

Helpful Hints for UNIX-Based Computers 25

Serial Cable 25

Basic Modem Settings for UNIX 25 Unix Software Tips 26

4 LCD Panel Operation 28

LCD Panel 28

Panel Operation 29

Menu Tree 30

LED Status Screen 30

Double Arrows on The Screen 31

Dialing 31

Dial Memory 32

Storing a Number 32

View and Store a Number 33


Dialing a Number 33 Manual Dial 34 Repeat Last Dial 35 Auto Answer 35

Dialing Messages 36 Panel Lock 41

V.25bis Command Set 42 Clock Options 43

RTS Options 44

Command State Options 44

Dialing from Synchronous Mode 44 Answering from Synchronous Mode 45

Auto-Answer 45 Manual Answer 45

5 Leased Line Operation 46

Connecting to a Leased Line 46

Power Level Setting 46

Leased Line Handshaking 46

Manual Connect 47

Auto Handshake 47

Aborting from Leased-Line Operation 47

Terminating a Leased Line Connection 48

6 Special Functions 50

Security Functions 50

Levels of Security 50

User Passwords 51

Remote Configuration 53

Caller Number Delivery (Caller ID) 54

Distinctive Ring 57


Extended Distinctive Ring (EDR) 59

Setting Up EDR 60

EDR Application Example 61

7 Fax Operation 64

Fax Basics 64

Modem as Fax Machine 65

ITU-T T.30 Fax Protocol 65

Fax Command sets 66

Defining the Fax Command Sets 66

Class 1 Command Set 67

Class 2 Command Set 68

Class 2.0 Command Set 74

Extended Fax AT Command Set 81

Flow Control 85

Fax Reception from a BBS 86

8 AT Command Set Summaries 88

Basic AT Command Set 88

Description of ATI2 Output: 91

Extended AT& Command Set 94

Extended AT* Command Set 100

9 Status Registers & Result Codes 105

S-Register Descriptions 105

Basic S-Registers "ATSn=x" 105

Extended S-Registers "ATSn=x" 106

Result Code Options 124

"ATXn" Result Code Option Table 124

Result Code Field Descriptions 126


Connect Strings for Error Corrected Connections 127

10 Diagnostics & Troubleshooting 128

Diagnostics 128

Power-On Self Test 128

Resetting The Modem 129

Loopback Tests 130

Indicator Lights 132

Line Condition Status Display 132

Trouble Shooting 135

AT Command Set Problems 135

Command Echo Problems 136

Answer Problems 137

Dialing Problems 138

Data Transfer Problems 138

Connection Problems 139

11 Upgrading Your Modem 140

Upgrading by Flash EPROM 140

Kernel Recovery Mode 141

12 Connector Pinouts 142

Phone Jack Pinouts 142

PC Serial Port Pinouts 142

Macintosh Serial Port Pinouts 144

13 Index 146


1 Introduction

Congratulations on the purchase of your U-336S/SA modem - one of ZyXEL's premier high-performance products. The U-336S and the U- 336SA modem are world renown for their ability to maintain ultra high speeds and clear, quality connections while communicating around the globe.

This User’s Guide describes the use of both U-336S and U-336SA models and gives instructions for their installation and operation. All the features are common to both the models except for different input terminal. The U-336S modem requires an AC power adapter whereas the U-336SA can be directly connected to the AC power outlet.

If you do not find information on a specific topic, or if you would like more information about a topic covered in your User's Manual, please call ZyXEL Technical Support at 714-693-0808. Other means of contacting ZyXEL are listed in the Contacting ZyXEL section.

Required Equipment

In addition to the ZyXEL modem you just purchased, you must have the following equipment to operate your modem:

Computer terminal.

Available PC serial port with a high-speed 16550 UART.

Standard "straight-through” RS-232 cable (pins 1-8, 20, 22).

Available telephone jack.

Introduction 1

One AC power adapter (external model) for U336S modem only.

Available AC wall outlet.

Telephone line from your telephone company (dial-up or leased line).

Data and fax communication software.

Modem Features

No other 33.6 Kbps modem gives you so much for so little. Your modem is equipped with an array of standard and ZyXEL-famous Intelligent features designed to make your data communications faster, easier, and more convenient.

Standard Features

Ultra-high speed modem supports V.34bis for 33,600bps and is backwards compatible

Operates in all environments including: Windows 95, DOS, Windows, Macintosh, OS/2, UNIX, Novell, Amiga, and IBM AS400/RS6000.

V.42 and MNP 4/3 error correction.

V.42bis and MNP 5 data compression.

DTE serial interface with speeds up to 460.8Kbps.

20 x 2 LCD display.

10 LED indicators.

2 Introduction

Extended AT command set with V.25bis.

Operates on 2-wire dial-up or 2-wire leased line.

Intelligent Features

Automatic data and voice call detection allows you to use a single telephone line to handle both types of calls.

Asynchronous and synchronous modes for reliable serial data communication.

Fast retrain with automatic fall-forward and fall-back. Your modem will automatically fall back to lower speeds when communicating with slower modems and when encountering unstable or variable line conditions.

Call-back security and password protection restricts access to authorized callers only.

Caller ID identifies incoming calls before you answer (you must subscribe to this service through your telephone company in order for your modem to identify callers).

Distinctive ring detects data and voice calls (this feature requires communication software that supports distinctive ring, such as ZFAX)

Remote configuration capability.

EDR (extended Distinctive Ring).

Flash EPROM memory lets you easily upload new firmware, providing you with easy access to new features.

Introduction 3

ZyXEL exclusive Kernel Recovery Mode for no hassle recovery from failed flash uploads - no factory repairs.

Fax Compatibility

EIA Class 1, 2, and 2.0 Fax commands.

ITU-T V.17 G3: up to 14,400bps.

ITU-T V.29 G3: up to 9,600bps.

ITU-T V.27ter G3: up to 4,800bps.

ZyXEL Fax AT commands.

Technical Specifications

Operating mode: auto-dial/answer.

Flow control: software XON/XOFF or hardware CTS/RTS.

Configuration settings: software programmable with non-volatile memory for phone number/profile storage.

Diagnostics: self test, analog loopback (with self test), digital loopback, and remote digital loopback (with self test).

Dialing type: tone/pulse dialing.

Line interface: 2-wire dial-up or 2-wire leased line.

Call progress monitoring: dial tone, busy, and ring back detection.

4 Introduction

Audio Monitor: programmable volume control.

Introduction 5

6 Introduction

2 Installation

This chapter describes the panel function and installation procedure for the U-336S/SA.

A shielded RS-232 cable is required to ensure compliance with FCC Part 15, and it is the responsibility of the user to provide and use a shielded RS-232 cable. Make sure your installation site is clean and well ventilated. The ventilation slot of your ZyXEL modem located on the sides and bottom should not be covered and should allow free movement of air.

Front Panel

The U-336S and the U-336SA models have 10 LED indicators, a 20 x 2 LCD display, and four key switches. The following figure shows the front panel of the U-336S.

Figure 2-1 Front Panel

The next figure shows the front panel of the U-336SA modem.

Installation 7

Figure 2-2 U-336SA Front Panel

Front Panel LEDs

PWR Power ON indicator, loghts up when your modem is turned ON.

OH Off-Hook indicator, lights up when your modem is in data mode or off-hook. It goes out when your modem is in talk mode or on-hook.

AAAuto-Answer indicator, lights up when your modem is in the Auto Answer Mode; flashes when modem rings. In error control mode, it flashes when retransmitting.

DTR Data Terminal Ready indicator, lights up when your DTE or computer indicates that it is ready to begin communication.

DSR DTE mode: Data Set Ready Indicator, lights up when the modem is ready for communication.

TXD Transmit indicator, ON when your DTE/computer transmits data on the serial port.

RXD Receive indicator, ON when your DTE/computer receives data on the serial port.

CD Carrier Detect indicator; lights up when a valid carrier is detected present on the line.

RTS DTE mode: Request To Send indicator; indicates the signal status of RS232 signal RTS from DTE. RTS is used for hardware flow control in asynchronous data transmission.

8 Installation

CTS DTE mode: Clear To Send indicator; lights up when modem can accept data for transmission. It indicates the signal status of RS232 signal CTS.

Front Panel Switches

The four arrow keys are for panel operations, allow intuitive menu tree operation and display modem status. Refer to Panel Operstion section in the Chapter LCD Panel Operation for details of menu key operations.

Rear Panel Markings

The U-336S/SA rear panels are shown below:

Figure 2-3 U-336S Rear Panel

Figure 2-4 U-336SA Rear Panel

Explanations of the connectors and switch on the rear panel are given below.


Installation 9

Power switch, turns the modem ON or OFF.


Input terminal for power. Use the supplied AC adapter for U-336S model. For U-336SA model you can use your power cord to directly connect to the AC power outlet.


Dial-up line RJ-11 terminal jack, for connection to a 2-wire dial-up or 2-wire leased line.


RJ-11 terminal jack, for connection to a telephone set.


Serial port DB25S connector, for connection to the serial port of a DTE (computer/terminal). Pin assignments are listed in Chapter 12 Connector Pinouts for your reference. The signal-pin assignments for RJ-11 phone jacks are also listed in Chapter 12 Connector Pinouts.

Modem Connection

When you connect your U-336S modem to the power line, make sure you only use the power adapter that is supplied with this unit. Use of another adapter may not allow your modem to operate and could result in serious damage to the unit.

This adapter is rated for direct connection to an AC power outlet. Connect your modem as shown in Figure 2-5 U-336S Modem Connections.

10 Installation

ZyXEL Communications U-336S, U-336SA User Manual

Figure 2-5 U-336S Modem Connections

For the U-336SA you don’t need an AC adapter. Use the supplied power cord to connect your modem to the AC power outlet.

Figure 2-6 U-336SA Modem Connections

If a leased line is not used, simply leave the connection open. There are no DIP switches or configuration settings that you need to worry about. Your modem comes factory pre-set and allows you to fully configure the modem from the LCD display. User configurations are also

Installation 11

conveniently stored in user selectable non-volatile memories and can be recalled as often as needed.

Powering Up

Once your modem’s power switch is turned ON, a series of diagnostic tests will be performed while a message is shown on the LCD panel. For a more detailed description of these diagnostic tests, please refer to Chapter 10 Diagnostics & Troubleshooting.

After performing the diagnostic tests, your modem will display the current modem settings on the LCD panel as shown below:

Your modem is now ready for use.












































Multi-auto V42b DL









115200 AS










































































































































































Figure 2-7 Idle Screen

12 Installation

3 Basic Modem Operation

This chapter covers the basic commands and techniques involved in modem operation. In many cases, this is the only information you will need in order to get up and running with communication software, and to start making connections with your modem.

Understanding AT Commands

The U-336S/SA communicates asynchronously with computers using AT commands. AT commands are used to configure and control your modem. Commands are usually sent to the modem by way of communication software, but can also be entered manually by the user with the computer keyboard.

Command statements must be written in a specific form in order for your modem to recognize them. A command statement always begins with the letters AT or at. It is then followed by one or more commands and the <Enter> key.

AT commands can only be issued when your modem is in “command mode” or “off-line.”

Once your modem has established a connection with another modem it is said to be “on-line” or in “data mode.” In this mode, the characters sent to your modem by your computer are transmitted to the remote modem rather than being interpreted by your modem as commands.

Basic Modem Operation 13

Using the Windows 95 Hyper Terminal


In order to issue an AT command statement, you first need to run a communication program such as the Microsoft Windows “Hyper Terminal” program. This program provides a simple method to manually enter AT commands so you can do such things as “customize” the settings of your modem, or store commonly used phone numbers.

Once your modem is connected to your computer’s serial port and telephone line, open the Windows 95 “Accessories” program group, and open the Hyper Terminal Program.

The program will prompt you for a name and Icon to use for your new connection. Type the name Test Connection and press <Enter>.

Next, you will be prompted for country information, area code and phone number, and the device used to make the connection. For this test purpose, do not enter a phone number; simply choose the COM port your modem is connected to from the “Connect Using” list. Click “OK” when finished.

The next window sets the COM port settings. The settings used for your modem should be as follows.

Bits per second:


Data bits:




Stop bits:


Flow Control:


Click “OK” when finished. After you have done this, save your new connection by selecting “Save” from the “File” menu and click “OK.” A new connection icon will be added to your Hyper Terminal folder.

14 Basic Modem Operation

You are now ready to start entering AT commands.

In the terminal window, type:


Your modem responds


This confirms that the modem and your computer are communicating correctly.

To test the telephone line connection issue the manual answer command.



Your modem will pick up the phone line, and try to communicate. Normally, this command is only used to answer an incoming call made from another modem, thus the high pitched tone you will hear from the speaker. To abort the operation, press any key, or select “Disconnect” from the “Call” menu.

Dialing and Answering Techniques

Depending on what communications software you use to make modem connections, you may not have as much control of how the modem dials the telephone number. This section shows some useful examples of the AT commands used for dialing and answering operations. The command characters specific to each function are shown in bold type.

Dialing using the ATD Command

Touch Tone Dialing:

ATDT 555 1212

Pulse Dialing:

ATDP 555 1212

Basic Modem Operation 15


Tone and Pulse Dialing:

ATDP 555 1212 WT 24


Dialing Through a PBX:

ATDT 9 W 555 1212







Pausing During Dialing:

ATDT 9,,555 1212







Dialing Without Waiting for Dial Tone:

ATX0D, 555 1212


Originating a call using an Answer Tone:

ATDT 555 1212,,,,,,R


Redialing the Last Number Called:



Waiting for Five Seconds of Silence: ATDT 800 555 1212 @



123456,1 714 555 1212


Transferring a Call (using flash hook): ATDT! 2468

Auto-Answer and Hook Controls


Enabling Auto-Answer:







Disabling Auto-Answer:



Manually Answering a Call:



Take modem off-hook:



Hang up modem (on-hook):



Manually Disconnecting a Call:


16 Basic Modem Operation

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