ClearOne GT1524 User Manual

GT1524 Single Channel Echo Canceller

Installation & Operation Manual

Technical Services Group ~ 1-800-283-5936 (USA) ~ 1-801-974-3760

rights reserved. No part of this document may

be reproduced in any form or by any means

without written permission from ClearOne

Communications, Inc. Printed in the United

States of America. ClearOne Communications

reserves specific privileges. Information in this

document is subject to change without notice.

GT1524 Installation and Operation Manual ClearOne Part No. 800-114-101 June 2002 (Rev. 2.0)

iii

Technical Services Group ~ 1-800-283-5936 (USA) ~ 1-801-974-3760

GT1524 Installation and Operation Manual

Table of Contents

CHAPTER 1: Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Professional Services Group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

Sales and Customer Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

ClearOne Communications EuMEA GmbH . . . . . . . . . . . . . . . . . . . .2

Product registration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

Product returns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Controls and Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Front panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Rear panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Operational Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Equipment placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Telephone line requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

CHAPTER 2: Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Hardware Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Connecting the unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

LCD Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Menu trees . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Input parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

CHAPTER 3: Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

Front Panel Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

Controlling volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

Muting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

Answering a call . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

Making a call . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

Disconnecting a call . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

Custom Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

Custom controller options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

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APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

Appendix A: Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

Appendix B: Pinouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Appendix C: Serial Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

Appendix D: Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

Appendix E: Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

Technical Services Group ~ 1-800-283-5936 (USA) ~ 1-801-974-3760

CHAPTER 1: Introduction

The GT1524 provides the highest possible audio quality available in a single channel

echo canceller. It features an integrated telephone interface that enables telephone

participants of an audio or video conference to sound as if they are actually in the

same room. Plus, it features simultaneous two-wire/four-wire operation so you can

audio conference and video conference at the same time. And there’s no white noise

setup; the GT1524 adapts automatically.

The GT1524 performs a variety of complex, integrated audio functions using

digital signal processors (DSPs). Adjustments in level and other functions can be

made via front panel programming, activation through a closure on the rear panel,

or an RS-232 serial interface.

The integrated telephone interface provides the GT1524’s audio conferencing

capability and can be customized to suit your needs. It can be set to automatically

answer upon detection of a valid ring and automatically disconnect on loop drop or

call progress tones. The GT1524 includes a built-in five-watt power amp. The amp

delivers 5W of output power into a 4Ω speaker, eliminating the need to provide

external amps for the speakers.

• Easy design, programming, installation, and maintenance.

• Each input incorporates automatic gain control to compensate for loud or

soft talkers, while the mic/line input offers high-pass filtering to reduce

unwanted low frequency noise.

• Integrated touch-tone dialing for easy dialing through remote control.

• ClearOne’s digital signal processing technology ensures crystal-clear audio

with the deepest, most reliable hybrid null.

• 8kHz sampling rate allows continual adaptation to telephone-line

conditions.

• Acoustic echo cancellation (single channel) >120 ms DSP bases.

• Full-time telco echo cancellation with 31 millisecond tail time.

• Lockout front panel access for security.

• Phoenix push-on blocks make pin-for-pin wiring easier.

Features

Introduction ~ Professional Services Group

Technical Services Group ~ 1-800-283-5936 (USA) ~ 1-801-974-3760

If you need any additional information on how to install, set up, or operate your

system, please contact us at one of the locations listed below. We welcome and

encourage your comments so we can continue to improve our products and serve

your needs.

ClearOne Communications ~ 1825 Research Way ~ Salt Lake City, UT 84119

Technical Support

Telephone: 1.800.283.5936 (USA) or 1.801.974.3760

Fax: 1.801.977.0087

E-mail: tech.support@clearone.com

Web site: www.clearone.com

Sales and Customer Service

Telephone: 1.800.945.7730 (USA) or 1.801.975.7200

Fax: 1.800.933.5107 (USA) or 1.801.977.0087

E-mail: sales@clearone.com

ClearOne Communications EuMEA GmbH

Leonhardstr. 16-18, D-90443 Nuremberg, Germany

Telephone: +49 911 955159-0

Fax: +49 911 955159-10

E-mail: global@clearone.com

Product registration

Please register your GT1524 online at

www.clearone.com.

When your product is

properly registered, ClearOne Communications is better able to serve you should you

require technical assistance. Registration information is also used to notify you of

upgrades and new product information.

Product returns

All product returns require a return authorization (RA) number. Please contact

ClearOne Technical Support before attempting to return your GT1524 unit.

Professional Services Group

Introduction ~ Unpacking

Technical Services Group ~ 1-800-283-5936 (USA) ~ 1-801-974-3760

Ensure that the following items were received with your shipment:

Front panel

A. LCD window. The two-line, 16-character-per-line LCD display is used for

the GT1524 setup. Level adjustments are made through a menu system and

four front-panel buttons [B]. Functions that can be accessed through the

front-panel LCD include setup, programming, troubleshooting, and numeric

audio level and gain readouts.

B. Enter/▲▼/Esc. These buttons are used to navigate the LCD menu system.

ClearOne Communications is not responsible for

product damage incurred during shipment. You must make claims directly with the carrier. Inspect your shipment carefully for obvious signs of damage. If the shipment appears damaged, retain the original boxes and packing material for inspection by the carrier. Contact your carrier immediately.

Unpacking

Figure 1.1. Unpacking Your GT1524

✍

Controls and Connections

Figure 1.2. GT1524 Front Panel Controls

GT1524

GT1524 PART 910-114-101

AC Power Cord PART 699-150-006

Optional

Speaker PART 910-103-010

+12

+8 +4

Enter

Meter

Esc

-4

-10

-30

12-foot Telephone Cable PART 830-000-012

Microphones PART 910-103-160 or 910-103-161 Mic Cables included (shown below)

Telephone

Off

Push-on Blocks (6) PART 673-016-003

GT1524 Manual PART 800-114-101

+12

+8 +4

Enter

Esc

A B C D E F

Meter

-4

-10

-30

Telephone

Off

Introduction ~ Controls and Connections

Technical Services Group ~ 1-800-283-5936 (USA) ~ 1-801-974-3760

C. LED Meter. The LED bar meter displays the audio level of any input or

output of the GT1524 as well as the Echo Return Loss (ERL) and Echo

Return Loss Enhancement (ERLE) between the Speaker/Line Out and the

Mic/Line audio input channel. The LED meter also displays Telco Echo

Return Loss (TERL) and Telco Echo Return Loss Enhancement (TERLE) for

the telephone hybrid.

D. Meter. This button displays the Meter branch of the GT1524’s LCD menu

tree from which you can view or enter settings.

E. On. The On button connects and adapts the GT1524 to the telephone line.

Pressing and holding the On button for more than two seconds while the

GT1524 is active sends a noise burst to readapt the unit to the phone line. A

short tone (1000Hz) is sent out the Speaker and Line outputs to indicate

that the GT1524 is connected to the line.

F. Off. The Off switch disconnects the GT1524 from the telephone line and

mutes all transmit audio to and from the telephone line. A short tone

(400Hz) is sent out the Speaker and Line Outputs to notify the user that the

GT1524 is disconnected from the line.

Rear panel

A. Power. This power module accommodates power ranging from

100–240VAC, 50/60Hz, 30W. No switching is required.

B. Line Out, Aux Out. These connection blocks are for line level outputs. The

Line Output is used for connection to an external power amplifier or sound

reinforcement system. The Aux Out is used for connection to recording

equipment, such as a VCR. The nominal output level is 0dBu.

C. 4 Wire/Video Codec In/Out. Connects four-wire transmission systems, such

as a video codec.

D. Mic/Line In, Aux In. The Mic/Line input is for connection of a local

microphone or input from a local sound system or mixer. The Aux In allows

input from other audio sources, such as a VCR or CD player. Nominal input

is 0dBu.

Figure 1.3. GT1524 Rear panel connectors

AB C D EF

Introduction ~ Operational Requirements

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E. RS-232. This female DB-9 serial port is for interconnection between the

GT1524 and a PC or custom remote control. See Appendix C for serial port

commands.

F. Control/Status. This female DB-25 connector is used to interface parallel

control and status to the GT1524. Control pins on this connector are used to

perform functions via a momentary closure to ground. Each status pin on

this connector shows the state of the function handled by the pin. Status pins

are open collector outputs. When active, the output is pulled to ground;

otherwise, the output is an open circuit. See Appendix B for control/status

port pinout information.

G. Speaker. One 5W, 4–16Ω speaker can be directly connected to the

GT1524, eliminating the need for a power amplifier.

H. Telco Line. Connects to your telephone line source.

I. Telco Set. Connects to your telephone handset.

Equipment placement

The GT1524 is designed for mounting in a 19-inch equipment rack. (Do not block

any of the ventilation holes.) With a desktop kit, the GT1524 can be modified for

tabletop placement.

Telephone line requirements

The GT1524 operates on a standard analog telephone line and connects to the

telephone system with a standard RJ-11C modular jack. If you do not have an

RJ-11C jack where you want to install the GT1524, call your telephone company for

installation.

Operational Requirements

Technical Services Group ~ 1-800-283-5936 (USA) ~ 1-801-974-3760

This chapter provides step-by-step instructions for installing your GT1524 system.

Figure 2.1 (below) shows the back panel connections of a fully-installed GT1524

system.

Connecting the unit

The power cord should be connected last. Otherwise, the order in which you connect

the cables is not important. Refer to the diagram shown in Figure 2.2 when making

connections.

1. Place the unit in a standard 19-inch rack and attach it securely.

2. Connect your telephone line from the wall jack to the RJ-11 Line jack [H].

3. Plug your telephone set into the RJ-11 Set Jack [I].

4. If you are using a custom controller for control and status, plug it into the

DB-25 Control/Status port [F].

CHAPTER 2: Installation

Figure 2.1. GT1524 installation

Hardware Setup

Figure 2.2. GT1524 Rear panel connectors

5W, 8Ω

Speaker

Analog

Telephone

Line

LINE OUT

Power Amp

AUX OUT

4 WIRE/VIDEO CODEC

OUT

MIC/LINE IN

AUX IN

Microphone

E R

E S

U N I

E T U

Video codec

AP IR Remote Control

Y D A

Logic out

status and

control

AB C D EF

Installation ~ LCD Programming

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5. Use the RS-232 port to connect the GT1524 to a PC (for use with

HyperTerminal), an AP IR Remote Control, or a custom remote control

device.

6. Connect an external amplifier or sound reinforcement system to Line Out.

Use Aux Out to connect recording equipment, such as a VCR. Nominal

output is 0dBu.

7. Using the included connectors, wire a 4-wire transmission system, such as a

video codec, to the 4 Wire/Video Codec In and Out connectors. Nominal

input/output is 0dBu.

8. Connect a local microphone or input from a local sound system or mixer to

Mic/Line In.

9. Connect the speaker wire to the + (red) and – (black) binding post

connectors.

10. Connect the power cable after making all other connections. As soon as

power is supplied to the unit, the GT1524 initializes and all front-panel

LEDs and the LCD light. The power module accommodates 100–240VAC,

50/60Hz, 22–30W.

For most installations, the default settings in the GT1524 do not need to be changed;

the system can be used as soon as power is applied. However, if you need to

customize any settings, such as telephone connection options or input parameters,

you can do so through the front panel user interface.

The front panel includes a 2x16 character LCD, menu buttons, and LED bar

meter. When power is applied to the GT1524, all LEDs light and the LCD panel

reads INITIALIZING. If initialization is completed without errors, a title screen

appears, showing the product name (top line) and the version number (bottom

line). The title screen remains on display until you initiate some action that writes

information to the LCD panel or the GT1524 detects and displays an error. If an

error is displayed, contact ClearOne Technical Support.

Menu trees

Four main menu trees (menu categories) comprise all of the GT1524 options you can

control through the front panel: Inputs, Outputs, System, and Meters (see Figure

2.4). Enter each of the trees by pressing the up/down buttons and scrolling to the

The three terminals in the Phoenix connector

correspond with the rearpanel audio contacts (from left to right): + (positive), – (negative), and



(ground).

✍

Figure 2.3. Phoenix push-on connector

LCD Programming

Inputs

Outputs

System

Meter

Figure 2.4. Main Menu Trees

ClearOne GT1524

Version x.x

Pressing ESC at the top of the tree has no effect.

Installation ~ LCD Programming

Technical Services Group ~ 1-800-283-5936 (USA) ~ 1-801-974-3760

appropriate menu. Then press Enter. To descend a menu level (go deeper into the

tree), press Enter. To ascend a menu level (go back toward the top of the tree),

press ESC.

The Meter button will also access the Meter tree directly. The menu trees are

structured in levels, such that the first level (top of the tree) branches into multiple

subcategories (see Figure 2.7). These branches typically end when an adjustable

parameter or viewable value is reached.

Adjusting a value

To adjust a parameter, first verify that it is flashing. If the parameter is not flashing,

it cannot be adjusted until you press Enter. If the parameter is flashing, adjust the

value with the Up and Down buttons. As the value is adjusted, the parameter is

updated immediately. For example, if you adjust input gain, you should be able to

hear the difference as it changes. To store the new value, press Enter. To discard the

change and revert back to the old value, press ESC. In general, while adjusting

parameters, numerical values do not wrap around when the end is reached. However,

parameters that toggle between two values (or are a list of values) will wrap around.

When adjusting a parameter, press and hold the Up or Down button for more than

two seconds to scroll through the values at a faster rate.

Figure 2.5. Front Panel Buttons

✍

)

(10)

(0)

Figure 2.6. Parameters Worksheet

Enter

+12

+8 +4

Esc

-4

-10

-30

Mete

GT1524 Parameters Worksheet

System-Wide Parameters

Program Parameter Selection Range

Lock Panel

Set Passcode

RS232 Baud Rate

RS232 Flow Control

Telco Auto Answer

Telco Auto Disconnect

Telco Ring Indication

Unit ID No. Factory Programmed

*Timeout

*Telco Adapt Mode

*Hook Duration *Receive Reduction

Meter

Program Parameter Selection Range

Default Meter

Input Channel

Program Parameter Selection Range

Gain Adjust

Mic/Line Input

Mute

Phantom Power

AGC

High-Pass Filter

Echo Cancellation NLP Adjust

Output Channel

Program Parameter Selection Range

Gain Adjust

Mute

Aux Out Mix (Mic/Line In) Aux Out Mix (Aux In)

* Set up only by serial port

On, Off

5 Front Panel Keys (Enter

9.6, 19.2, 38.4 kbps

On, Off

Off, Loop Drop, Call Pro

Off, 1, 2, 3, 4

0 - 15

Auto, Burst

50 ms, 500 ms On, Off

Any Input/Output (Spkr/Line Out)

-20dB to 20dB

Mic 55dB, Mic 25 dB, Line

On, Off

On, Off Off, Soft, Medium, Aggressive

-20dB to 20dB

On, Off

On, Off On, Off

, LD + CP

Mic/Line In Aux In 4 Wire In From Telco

Spkr/Line Out Aux Out 4 Wire Out To Telco

+ 29 hidden pages