Gentner GT300 User manual

GT300 and GT700
Installation and
Operations Manual

The connection ports on the GT300/GT700 are to be used as follows:
Power Connection to the power cord provided
Speaker Connection to external speaker(s)
Remote Control Connection to external Gentner remote control
RS232 Connection to external non-Gentner remote control
Room Transmit Connection to external mixer
Room Receive Connection to external mixer
Tape Record Connection to external tape recorder
Bridge Connection to additional telephone-interface equipment
Tape Play Connection to external tape player or VCR
Microphone Connection to external microphone(s)
Four-Wire Receive Connection to external video CODEC
Four-Wire Transmit Connection to external video CODEC
Telephone Line Connection to telephone line
Telephone Set Connection to telephone set
Gentner Communications Corporation is committed to protecting the environment
and preserving our natural resources.
This manual has been printed entirely on recycled paper.
This equipment complies with the requirements of the EU guidelines:
89/336/EEC “Electromagnetic Compatibility”
73/23/EEC “Electrical operating material for use within specific
voltage limits”
Conformity of the equipment with the above guidelines is attested by the CE mark.
© Copyright 1996 Gentner Communications Corporation. All rights reserved. No part of this manual may be
reproduced in any form or by any means without written permission from Gentner Communications Corporation.
Printed in the United States of America. Original version, 1/93. Gentner Communications Corporation reserves
specification privileges. Information in this manual is subject to change without notice.
GT Installation and Operations Manual
Gentner Part No. 800-110-300 (Rev. 2.00)
November 1996
Manual Development: Bill Kilpack
Artwork and IIlustrations: Mike Greenhalgh, Bill Kilpack
Copyright
Information

Contents
Introduction 1
Warranty Registration 1
Unpacking 1
Tools Required 2
Features and Benefits 2
Product Description 2
Model GT300 2
Model GT700 2
Adjustable Settings 3
Echo Elimination 3
Noise Filtering 3
Two-Wire (Telephone) and Four-Wire (Video) Modes 3
Microphones and Speakers 3
Accessories 3
Before You Install 3
Acoustic Room Treatment 3
Power Requirements 4
Telephone Line Requirements 4
Telephone 4
Video CODEC 4
Auxiliary Equipment 4
Equipment Placement 5
Environmental Requirements 5
Installation 5
Completed Installation 5
Step 1 — Placement 5
Step 2 — Make Connections 6
Calibration 8
Front Panel Controls 8
Four-Wire (Video) Conference 8
Two-Wire (Telephone) Conference 8
Room Transmit Level Ajustment 8
4 Wire/Video Transmit Level Adjustment 9
4 Wire/Video Receive Level Adjustment 9
Room Receive Level Adjustment 9
Automatic Setup 9
Volume + and Volume – 10
Front Panel Security 10
Operation 11
Videoconferencing 11
Teleconferencing 11
Increasing Listening Volume 12
Decreasing Listening Volume 12
Restoring Listening Volume to Default 12
Phone Add Option 13
Remote Control Option 13
Emergency Restoration 13
When Not in Use 14
Two-Wire (Telephone) Teleconferencing 14
Four-Wire (Video) Teleconferencing 14
Bridging Multiple Calls 15
Specifications 16
Warranty 17
GT Installation and Operations Manual Page iii
Technical orSetupAssistance
Telephone:[phone] (USA) or801.975.7200 (worldwide)•WorldwideWeb @ http://www.gentner.com

Contents continued
List of Tables
Table 1. Remote Control DB15 Connector Pinouts 22
Table 2. RS232 DB-9 Connector Pinouts 22
Table 3. Bridge DB-9 Connector Pinouts 22
Table 4. Telephone Set and Line Connections 22
Table 5. GT Serial Port Commands 23
List of Figures
Figure 1. Equipment diagram 1
Figure 2. System block diagram 5
Figure 3. GT numbered back panel 6
Figure 4. GT power module 6
Figure 5. GT speaker connector 6
Figure 6. GT remote control DB15 connector 6
Figure 7. GT RS232 DB9 connector 6
Figure 8. GT mixer audio XLR connectors 6
Figure 9. GT auxiliary equipment RCA jack 7
Figure 10. GT bridge connector and cable 7
Figure 11. Microphone DB9 connector 7
Figure 12. Four-wire (video) XLR connectors 7
Figure 13. GT RJ11C telephone-line connector 8
Figure 14. GT front panel controls 8
Figure 15. Factory default trim-pot position 8
Figure 16. GT front panel controls 10
Figure 16a.Front panel controls 12
Figure 17. Two-GT connection 14
FCC Part 15 Compliance 18
FCC Part 68 Compliance 18
IC Compliance 19
Safety Information 19
BABT Recording Requirements 20
Appendix A: Glossary 21
Appendix B: Connector Pinouts 22
Appendix C: Available Options 23
Appendix D: Serial Port Commands 23
Appendix E: PC Command Quick Reference 27
Appendix F: GT Block Diagram 28
Page iv GT Installation and Operations Manual
Technicalor SetupAssistance
Telephone:[phone] (USA)or 801.975.7200 (worldwide) •WorldwideWeb @ http://www.gentner.com

GT Installation and Operations Manual Page 1
Technicalor SetupAssistance
Telephone:[phone] (USA)or 801.975.7200 (worldwide) •WorldwideWeb @ http://www.gentner.com
Congratulations on purchasing the GT Group Teleconferencer. All GT models
use the latest digital technology, and contain a built-in microphone preamplifier
and speaker driver, eliminating the need to buy additional equipment.
The GT700 supports video and audio teleconferencing. An echo-cancellation
span of 112 milliseconds coupled with a frequency response of 7kHz (frequency
response of most video systems) translates into higher audio quality.
The GT was designed to work in almost any acoustic environment using most
kinds of peripheral equipment. Although many acoustic factors come into play in
the design and layout of conference facilities, the GT was built with superior
acoustic-cancellation features to provide the most trouble-free, acoustically
pleasing conference possible. The GT series models are complete systems with
with the addition of two microphones and a speaker (sold separately).
This manual explains how to install, set up and operate of your GT system. It
also provides instructions on how to improve room acoustics and resolve minor
technical problems, should any arise.
If you need information on how to install, set up or operate your system, please
contact Gentner Communications Corporation at the location noted below. We
welcome and encourage your comments so we can continue to improve our
products and serve your teleconferencing needs.
Gentner Communications Corporation
1825 Research Way
Salt Lake City, Utah 84119
TEL: Worldwide [phone] In U.S.A. [phone]
FAX: Worldwide [phone] In U.S.A. [phone]
FAX-On-Demand 24-Hour Information Service [phone]
Worldwide Web Page @ http:\\www.gentner.com
Please register your GT by completing the self-addressed, postage prepaid
warranty registration card and return it to Gentner Communications by mail. You
may also FAX it to the above listed fax number or call Gentner Communications.
When your product is properly registered, Gentner Communications will be able
to serve you better should you require technical assistance or desire to receive
upgrades, new product information, etc.
Ensure that the following equipment (See Figure 1, below.) was received with
your shipment:
SHIPPING NOTE:
Gentner 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.
Introduction
Warranty
Registration
Unpacking
Figure 1. Equipmentdiagram

Page 2 GT Installation and Operations Manual
Technical orSetup Assistance
Telephone:[phone] (USA) or801.975.7200 (worldwide) •WorldwideWeb@http://www.gentner.com
Tools Required
Small flat-head screwdriver (for fine tuning adjustment pots)
Medium Phillips screwdriver (if rack mounting)
Two models to meet your equipment and budget requirements
Superior acoustic echo cancellation
100-percent digital audio processing
Full-duplex operation
Digital gain processing
Auto answer/disconnect
Built-in microphone preamplifier
Built-in speaker driver
Privacy button for private conversations
Either two-wire (telephone) or four-wire (video) operation
Sleek design for in-room or rack installation
Reliable operation and setup integrity
Optional remote control
The GT series models contain superior digital echo-cancellation circuitry for both
video and audio applications.
Model GT300
The GT300 operates with a 3.4kHz bandwidth and at least 112 millisecond
acoustic echo-cancellation span. It is designed for use in both video and
audio applications. The GT300 contains a built-in microphone preamplifier
and speaker driver. This product’s audio performance will serve the needs of
most conferencing applications, both current and future. Your GT300 comes
complete with a Quick Reference Guide, and GT300 and GT700 Installation
and Operations Manual.
Model GT700
The GT700 contains superior digital echo-cancellation circuitry for both
video and audio applications. The GT700 operates with a 7kHz bandwidth
for higher audio quality. Due to its higher bandwidth (compatible with most
videoconferencing systems), the GT700 is best suited for videoconferencing
applications. This product contains a built-in microphone preamplifier and
speaker driver. Your GT700 comes complete with a Quick Reference Guide,
and GT300 and GT700 Installation and Operations Manual.
Features and
Benefits
Product
Description

GT Installation and Operations Manual Page 3
Technicalor SetupAssistance
Telephone:[phone] (USA)or 801.975.7200 (worldwide) •WorldwideWeb @ http://www.gentner.com
Adjustable Settings
Both GT series models contain adjustable transmit and receive trim pots, to
match your room and network equipment levels. Each system also contains a
simple setup procedure, and switches for echo cancellation and echo
suppression that can be individually set to accommodate your room’s specific
needs.
Echo Elimination
Front-panel acoustic echo canceller and acoustic echo suppressor LEDs will
flash green/red, graphically indicating whether echo cancellation and/or echo
suppression controls are working adequately. Both GT series models operate
with a 112-millisecond acoustic echo-cancellation span.
Noise Filtering
Internal filters remove unwanted noise: GT300 — below 300Hz and above
3.4kHz; GT700 — below 50Hz and above 7kHz.
Two-Wire (Telephone) and Four-Wire (Video) Modes
Both GT series models will operate in either two-wire (telephone) or four-
wire (video) modes. The front panel contains a two-wire (telephone) and a
four-wire (video) push-on/push-off button with LEDs to indicate which mode
is active. Assuming your equipment supports it, the GT series models
provide the audio in videoconferencing applications.
Microphones and Speakers
The GT series models contain a built-in microphone mixer and speaker
driver. This enables the system to sum audio from up to three microphones
and deliver up to 3W of output power to drive a 4ohm speaker. If more
microphones or speakers are required, a Gentner MPAII Mixer/Power
Amplifier may be added (an eight-channel automatic mixer with a two-
channel 15W power amp).
Accessories
The GT series models can be accessorized with an optional remote-control
device, speakers and microphones, and all cabling required for setup. See
Appendix C (Page 19) for a complete listing of accessories.
The GT is designed to work in almost any acoustic environment. To maximize
your teleconference audio quality, we recommend that you prepare your
teleconferencing site by taking the following factors into consideration:
Acoustic Room Treatment
Conference room treatment is recommended to improve the operation of your
teleconferencing system. Rooms that have large areas of windows, white
boards, hard floors, etc., are acoustically “live.” These areas increase the
amount of audio reverberation in the room which, in turn, reduces the audio
quality of your teleconference. You should minimize the amount of audio
reverberation where possible.
Before You
Install

Page 4 GT Installation and Operations Manual
Technical orSetup Assistance
Telephone:[phone] (USA) or801.975.7200 (worldwide) •WorldwideWeb@http://www.gentner.com
You can improve room acoustics by installing acoustic panels, drapes and
other wall fabrics. Another way to improve overall room acoustics is to keep
room noise (i.e. computers and fans) to a minimum.
Power Requirements
The GT series models automatically accommodate voltage requirements
ranging from 85–240Vac 50/60Hz power. No switching is required.
Telephone Line Requirements
For normal two-wire (telephone) audio teleconferencing operation, your GT
works on standard analog telephone lines and connects to the telephone
system with a standard RJ11C modular jack. If you do not have an RJ11C
jack where you want to install your GT, call your telephone company for
installation.
If you are connecting your GT to a PBX system, contact your telephone-
equipment manufacturer or service representative. Some PBX systems will
not work with your GT. Your GT works with the same type of telephone line
that a FAX machine or modem uses.
If you are using your GT for four-wire (video) conferencing, the line you
need to order from your local telephone company will be specified by the
CODEC, or other transceiver manufacturer whose equipment you have
purchased.
Telephone
A single-line analog telephone set will be required at time of installation and
for use during operation to initiate telephone calls.
Video CODEC
If you will be using the GT in four-wire (video) mode, a video circuit must be
supplied by the user. This device, such as a video CODEC, uses special lines
for handling transmission and reception of video and audio signals. Your
equipment must match the audio input and output requirements of the GT
four-wire (video) connection (i.e. transmit output and receive input). Check
Specifications (Page 15) for this information.
The audio from the GT is compatible with most popular CODECs, satellite
transceivers, fiber-optic transceivers or dedicated four-wire telephone
interfaces, regardless of transceiver or network delays. The four-wire (video)
connection is not capable of plugging directly into two telephone lines; a
four-wire telephone interface is required.
VIDEOCONFERENCING NOTE:
Gentner Communications strongly advises using a qualified sound contractor or
audiovisual specialist when installing equipment and circuitry for
videoconferencing.
Auxiliary Equipment
Any auxiliary equipment to be used with the GT (i.e. microphones, speakers,
recording equipment, etc.) should be available at time of installation.
Before You Install
Continued

GT Installation and Operations Manual Page 5
Technicalor SetupAssistance
Telephone:[phone] (USA)or 801.975.7200 (worldwide) •WorldwideWeb @ http://www.gentner.com
Equipment Placement
The GT can be placed on a cart or table in the conference room or other
nearby location (up to 1,000 feet from the conference room). The cabinet is
designed for office or conference room display. Rubber “feet” are included to
protect your table surface.
If your application requires mounting the GT in a 19" equipment rack, rack-
mount ears are supplied with each GT. For rack-installation instructions, see
Step 1 — Placement (below).
Connectors/Cables
The power cable is provided with your GT to connect the unit to an electrical
outlet.
When purchased as part of a system (which includes one speaker and two
microphones), the speaker wire is supplied.
Environmental Requirements
The GT can be safely operated in a room with varying temperatures between
32° and 100° F.
Follow these step-by-step instructions to install your GT:
Completed Installation
The following block diagram (See Figure 2, below.) shows the GT system
when installation is complete.
Step 1 — Placement
Your system is shipped for desktop or cabinet placement. Place the GT in a
convenient place in the conference room, on a table, or in a cabinet.
Rack-mount ears are included in the shipment for converting to a rack-
mountable unit, if desired.
1) Remove the two screws from the side panels and retain for later use.
Installation
Figure 2.Systemblock diagram

Page 6 GT Installation and Operations Manual
Technical orSetup Assistance
Telephone:[phone] (USA) or801.975.7200 (worldwide) •WorldwideWeb@http://www.gentner.com
2) Remove the decorative end caps from the side panels.
3) Place the rack ears on the sides of the GT unit, with the ears facing out.
4) Secure the rack ears to the side panels with the same screws.
5) Remove the rubber feet from the bottom of the GT, if necessary.
6) Mount the unit in a standard 19" equipment rack using the screws
provided. Do not block any ventilation holes.
Step 2 — Make Connections
Refer to GT back panel connections (See Figure 3, below.) for a description
and placement of each of the connections you will be making.
Each connection is numbered for easy identification.
Power
The power cord [1] (See Figure 4, left.) will operate at any level between 85–
240Vac, 50–60Hz.
Speaker
One 3W, 4–16ohm speaker can be directly connected to the GT (See Figure
5, left.), eliminating the need for a power amplifier. Connect the speaker
wire to the + (red) and - (black) binding post connectors [2].
Remote Control
If using Gentner’s optional remote control, plug it into the DB15 connector
[4] (See Figure 6, left.) labeled REMOTE. For pinouts, see Appendix B
(Page 19).
Or
If using another manufacturer’s remote control, plug it into either the DB15
REMOTE connector [4], or into the RS232 connector [3] (See Figure 7,
left.), depending on the manufacturer’s connector requirements. The
detailed RS232 protocol is included in Appendix D (Page 19).
Mixer Audio
Connect the mixer’s MASTER OUTPUT to the ROOM TRANSMIT input
female XLR socket [5] (Figure 8, left). This audio is sent to the remote
conference site.
Connect the GT’s ROOM RECEIVE output male XLR plug [6] to the power
amplifier input (PA IN on the MPA). This is balanced line-level audio
(audio from the other location). This audio will be amplified and sent to the
speakers.
Installation
Continued
Figure 3. GT numbered back panel
Figure 4. GT power module
Figure 5.GT speaker connector
Figure 6.GT remote control DB15
connector
Figure 7. GT RS232 DB9 connector
Figure 8. (Top)GT mixeraudiofemale
XLR connector;(Bottom) male XLR
connector