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GT724
Installation and
Operations Manual
Copyright
Information
© 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, 6/96. Gentner Communications Corporation reserves
specification privileges. Information in this manual is subject to change without notice.
GT724 Installation and Operations Manual
Gentner Part No. 800-114-001 (Rev. 1.00)
December 1996
Manual Development: Bill Kilpack
Artwork and IIlustrations: Mike Greenhalgh
The connection ports on the GT724 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
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
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.
Gentner Communications Corporation is committed to protecting the environment
and preserving our natural resources.
This manual has been printed entirely on recycled paper.
GT724 Installation and Operations Manual
Page iii
Contents
Introduction
Warranty Registration
Unpacking
Tools Required
Features and Benefits
Product Description
Adjustable Settings
Echo Elimination
Noise Filtering
RS232 Touch-Tone Dialing
Two-Wire (Telephone)/Four-Wire (Video) Operation
Remote Diagnostics Option
Microphones and Speakers
Accessories
Before You Install
Acoustic Room Treatment
Power Requirements
Telephone Line Requirements
Telephone
Video CODEC
Auxiliary Equipment
Equipment Placement
Environmental Requirements
Installation
Completed Installation
Step 1 — Placement
Step 2 — Make Connections
Calibration
Front Panel Controls
Four-Wire (Video) Cnference
Two-Wire (Telephone) Conference
Room Transmit Level Adjustment
4 Wire/Video Transmit Level Adjustment
4 Wire/Video Receive Level Adjustment
Room Receive Level Adjustment
Automatic Setup
Volume + and Volume –
Front Panel Security
Operation
Videoconferencing
Teleconferencing
Increasing Listening Volume
Decreasing Listening Volume
Restoring Listening Volume to Default
Remote Control Option
Emergency Restoration
When Not in Use
Two-Wire (Telephone) Teleconferencing
Four-Wire (Video) Teleconferencing
Bridging Multiple Calls
Specifications
Warranty
FCC Part 15 Compliance
FCC Part 68 Compliance
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Technical or Setup Assistance
Telephone: 800.945.7730 (USA) or 801.975.7200 (worldwide) • Worldwide Web @ http://www.gentner.com
Page iv
GT724 Installation and Operations Manual
Contents continued
IC Compliance
Safety Information
BABT Recording Requirements
Appendix A: Glossary
Appendix B: Connector Pinouts
Appendix C: Available Options
Appendix D: Serial Port Commands
Appendix E: PC Command Quick Reference
Appendix F: GT724 Block Diagram
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List of Figures
Figure 1. Equipment diagram
Figure 2. System block diagram
Figure 3. GT724 numbered back panel
Figure 4. GT724 power module
Figure 5. GT724 speaker connector
Figure 6. GT724 remote control DB15 connector
Figure 7. GT724 RS232 DB9 connector
Figure 8. GT724 mixer audio XLR connectors
Figure 9. GT724 auxiliary equipment RCA jack
Figure 10. GT724 numbered back panel
Figure 11. Microphone DB9 connector
Figure 12. Four-wire (video) XLR connectors
Figure 13. GT724 RJ11C telephone-line connector
Figure 14. Front panel controls
Figure 15. Factory default trim-pot position
Figure 16. GT724 Front panel controls
Figure 17. Factory default trim-pot position
Figure 18. Front panel controls
Figure 18a.Front panel controls
Figure 18b.Front panel controls
Figure 19. Two-GT724 connection
Figure 20. GT724 power-up message
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List of Tables
Table 1.
Table 2.
Table 3.
Table 4.
Table 5.
Remote Control DB15 Connector Pinouts
RS232 DB9 Connector Pinouts
Telephone Set and Line Connections
DB9 Microphone Connector Pinouts
GT724 Serial Port Commands
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Technical or Setup Assistance
Telephone: 800.945.7730 (USA) or 801.975.7200 (worldwide) • Worldwide Web @ http://www.gentner.com
GT724 Installation and Operations Manual
Introduction
Page 1
Congratulations on purchasing the GT724 Group Teleconferencer. The latest
digital technology has been incorporated into this outstanding product to support
audio for video and telephone teleconferencing through simultaneous two-wire
(telephone)/four-wire (video) operation. It incorporates an echo cancellation span
of 112 milliseconds with a bandwidth of 7kHz (the bandwidth of most video
systems). This higher bandwidth translates into higher audio quality. Also, the
GT724 incorporates touch-tone dialing through the RS232 port. The GT724
system will meet the growing needs of any organization — from small to large.
The GT724 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 GT724 was built with superior
acoustic-cancellation features to provide the most trouble-free acoustically
pleasing conference possible.
This manual explains how to install, set up and operate your GT724 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 801.975.7200 In U.S.A. 800.945.7730
FAX: Worldwide 801.977.0087 In U.S.A. 800.933.5107
FAX-On-Demand 24-Hour Information Service 800.695.8110
FAX-On-Demand International Line 801.974.3661
Worldwide Web Page @ http:\\www.gentner.com
Warranty
Registration
Please register your GT724 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 number or visit Technical Support at the Gentner
Worldwide Web Page and register your product online. 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.
Unpacking
Ensure that the following equipment (See Figure 1, below.) was received with
your shipment:
Figure 1. Equipment diagram
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.
Technical or Setup Assistance
Telephone: 800.945.7730 (USA) or 801.975.7200 (worldwide) • Worldwide Web @ http://www.gentner.com
Page 2
GT724 Installation and Operations Manual
Tools
Required
Small flat-head screwdriver (for fine tuning adjustment pots)
Medium Phillips screwdriver (if rack mounting)
Features and
Benefits
Simultaneous two-wire (telephone)/four-wire (video) operation with a single unit
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
Touch-tone dialing through the RS232 port
Remote diagnostics option
Reliable, simple operation and setup integrity
Product
Description
The GT724 is specifically designed as the audio interface for videoconferences
that require simultaneous audioconferencing via the telephone, operating with a
7kHz bandwidth (compatible with most videoconferencing systems) for higher
audio quality. This product contains a built-in microphone preamplifier and
speaker driver, and incorporates touch-tone dialing through the RS232 port.
Adjustable Settings
The GT724 contains adjustable transmit and receive trim pots to match your
room and network equipment levels. It also contains a simple setup
procedure and switches for echo cancellation and echo suppression that can
be individually set to accommodate your specific room’s 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. The GT724 operates with
a 112-millisecond acoustic echo-cancellation span.
Noise Filtering
Internal filters remove unwanted noise: two-wire (telephone) circuits —
below 300Hz and above 3.4kHz; four-wire (video) circuits — below 50Hz
and above 7kHz.
Technical or Setup Assistance
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GT724 Installation and Operations Manual
Page 3
RS232 Touch-Tone Dialing
Through the RS232 port, the GT724’s touch-tone (DTMF) dialing capability
can be accessed. This allows outbound calls to be initiated by the GT724
without requiring an external dialer or telephone set. This feature continues
to function after connection, to issue tones for voice mail/pager interaction.
Two-Wire (Telephone)/Four-Wire (Video) Operation
GT724 operates in two-wire (telephone) mode, four-wire (video) mode or
two-wire (telephone)/four-wire (video) modes simultaneously. Therefore, the
GT724 is a one-box audio solution in videoconferencing applications
(assuming your equipment supports it), as well as for telephone
audioconferencing applications.
Remote Diagnostics Option
With the optional Teleconferencing Tools software, diagnostics can be
accomplished locally with a PC connected directly to the RS232 port, or they
can be performed remotely, via a standard telephone line and modem
connected to the RS232 port.
Microphones and Speakers
GT724 contains a built-in microphone mixer and speaker driver. This
enables the system to sum audio from up to three microphones and deliver up
to 5W 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 GT724 can be accessorized with an optional remote-control device,
speakers and microphones, and all cabling required for setup. See Appendix
C (Page 23) for a complete listing of accessories.
Technical or Setup Assistance
Telephone: 800.945.7730 (USA) or 801.975.7200 (worldwide) • Worldwide Web @ http://www.gentner.com
Page 4
GT724 Installation and Operations Manual
Before You
Install
The GT724 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.
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 GT724 automatically accommodate voltage requirements ranging from
85–240Vac 50/60Hz power. No switching is required.
Telephone Line Requirements
For normal telephone audioconferencing operation, your GT724 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 at your
installation site, call your telephone company for installation.
If you are connecting your GT724 to a PBX system, please contact your
telephone-equipment manufacturer or service representative. Some PBX
systems will not work with your GT724; your GT724 works with the same
type of telephone line that a FAX machine or modem uses.
Telephone
A single-line analog telephone set will be required at time of installation and
for use during operation (if not using the RS232 touch tones) to initiate
telephone calls.
Video CODEC
If you will be using the GT724 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 GT724 (i.e. transmit output and receive input). Check
Specifications (Page 18) for this information.
The audio from the GT724 is compatible with most popular CODECs,
satellite transceivers, fiber-optic transceivers or dedicated four-wire
telephone interfaces, regardless of transceiver or network delays. The fourwire (video) connection cannot connect directly into two telephone lines; a
four-wire telephone interface is required.
Technical or Setup Assistance
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GT724 Installation and Operations Manual
Page 5
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 GT724 (i.e. microphones,
speakers, recording equipment, etc.) should be available at time of
installation.
Equipment Placement
The GT724 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 in a 19" equipment rack, rack-mount
ears are supplied with each GT724. For rack-installation instructions, see
Step 1 — Placement (next page).
Environmental Requirements
The GT724 can be safely operated in a room with varying temperatures
between 32° and 100° F.
Technical or Setup Assistance
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Page 6
GT724 Installation and Operations Manual
Installation
Follow these step-by-step instructions to install your GT724:
Completed Installation
The following block diagram (See Figure 2, below.) shows the GT724
system when installation is complete.
Figure 2. System block diagram
Step 1 — Placement
Your system is shipped for desktop or cabinet placement. Place the GT724
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 rackmountable unit, if desired.
Convert to Rack Placement
1) Remove the two screws from the side panels and retain for later use.
2) Remove the decorative end caps from the side panels.
3) Place the rack ears on the sides of the GT724, 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 GT724, if necessary.
6) Mount the unit in a standard 19" equipment rack using the screws
provided.
Step 2 — Make Connections
Refer to GT724 back-panel connections (See Figure 3, next page, top.) for a
description and placement of each of the connections you will be making.
Each connection is numbered for easy identification.
Technical or Setup Assistance
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GT724 Installation and Operations Manual
Page 7
Figure 3. GT724 numbered back panel
Power
The power module [1] (See Figure 4, left.) will operate at any level between
85–240Vac, 50–60Hz.
Speaker
One 5W, 4–16ohm speaker can be directly connected to the GT724 (See
Figure 5, left.), eliminating the need for a power amplifier. Connect the
speaker wire to the + (red) and - (black) binding post connectors [2].
Figure 4. GT724 power module
Remote Control
If using Gentner’s optional remote control, plug it into the DB15 REMOTE
connector [4] (Figure 6, left). For pinouts, see Appendix B (Page 22).
Or
Figure 5. GT724 speaker connector
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 23).
Figure 6. GT724 remote control DB15
connector
Figure 7. GT724 RS232 DB9 connector
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 GT724’s ROOM RECEIVE output male XLR plug [6] to the
power amplifier input (PA In on the MPAII). This is balanced line-level
audio (audio from the other location). This audio will be amplified and sent
to the speakers.
Auxiliary Equipment
If an audio tape or video recorder is to be used to record both sides of the
teleconference, connect a cable between the “record in” or “audio in” of your
recording device and the GT724’s TAPE RECORD jack [7].
To allow for audio playback (if you want to play a recorded tape to both
locations), plug in the “audio out” or “line out” connector from your VCR or
audio tape device into the TAPE PLAY jack [8] (Figure 9, left, bottom). The
audio is mixed with the receive audio for playback in the local room and is
also sent to the remote location.
Figure 8. (Top) GT724 mixer audio
female XLR connector; (Bottom) male
XLR connector
VCR NOTE:
VCRs that loop record audio to the play output may cause echo and/or feedback.
For more information, contact Gentner Communications at the number below.
If an audio tape player or VCR is connected to the GT724 for audio
transmission to the other site, turn the audio source on and adjust the PLAY
LEVEL trim pot [9] on the GT724’s back panel. This volume control will
adjust the audio level being sent to both the local and the remote rooms.
Figure 9. GT724 auxiliary equipment
RCA jack
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Page 8
GT724 Installation and Operations Manual
Figure 10. GT724 numbered back
panel
Figure 11. Microphone DB9 connector
Microphone
Plug up to three microphones into the provided three-way splitter. Plug the
splitter into the MICROPHONE DB9 connector [10] (See Figure 10, above;
Figure 11, left.) to take advantage of the GT724’s internal microhone mixer.
For pinouts, see Appendix B (Page 22).
Four-Wire (Video) Connections
When connecting your GT724 to four-wire (video) equipment, connect the
transceiver or CODEC output to the GT724’s 4 WIRE/VIDEO RECEIVE
input [11] (female XLR connector; Figure 12, left). Check your equipment
manufacturer’s documentation to verify proper connector assignment and
specifications.
Connect the GT724’s 4 WIRE/VIDEO TRANSMIT output [12] (male XLR
connector; Figure 12,left) to the input of the transceiver or CODEC. Check
your equipment manufacturer’s documentation to verify proper connector
assignment and specifications.
Figure 12. (Top) Four-wire (video) receive
female XLR connector; (Bottom) four-wire
(video) transmit male XLR connector
LEVEL/IMPEDANCE NOTE:
Check Specifications (Page 18) for proper level and impedance for both male
and female XLR connections.
Connect Telephone
Plug your telephone line from the source into the RJ11C LINE jack [13]
(Figure 13, left, bottom).
Plug your telephone set into the RJ11C SET jack [14].
Figure 13. GT724 RJ11C telephoneline connector
Technical or Setup Assistance
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GT724 Installation and Operations Manual
Calibration
Page 9
The following information will help you make adjustments to optimize your
system performance. Verify all components (including microphones and
speakers, mixer/power amplifier, CODEC, bridged and auxiliary equipment, etc.)
and all connections (see Step 2 — Making Connections, Page 6). Ensure that
proper power is supplied to the GT724.
Front Panel Controls
Refer to GT724 front panel controls (See Figure 14, below.) for numbered
easy identification.
Figure 14. GT724 front panel controls
Move the front-panel slider to expose the trim pots and switches.
CALIBRATION NOISE NOTE:
Some echo and ringing may be heard while calibrating the GT724. Disregard it
and continue with calibration until the end of the procedure. The echo and
ringing will disappear.
The TELEPHONE [29] and 4 WIRE/VIDEO [27] push-on/push-off activate
and deactivate the respective modes.
Place the AEC [23] switch in the ON position and the AES [25] switch in the
OFF position.
Check trim pots [15, 17, 19, 21]. Each adjustment level should be in the
(nominal) factory-default position (approximately one-fourth open or in the
10 o’clock position; Figure 15, left).
Four-Wire (Video) Conference
Figure 15. Factory default trim-pot position
To initiate a four-wire (video) conference, press the 4 WIRE/VIDEO button
[27]. The 4 WIRE/VIDEO LED [26] will light and the red PRIVACY LED
[30] will extinguish.
Two-Wire (Telephone) Conference
To initiate a two-wire (telephone) conference, call the remote party using the
telephone set. Wait for the party to answer, then press the TELEPHONE
button [29]. The TELEPHONE LED [28] will light. Once the button is
pressed, you may hang up the handset.
FOUR-WIRE NOTE:
If the GT724 is not in the four-wire (video) mode prior to the two-wire
(telephone) connection, the 4 WIRE/VIDEO LED [26] will also light when the
TELEPHONE button [29] is pressed.
Technical or Setup Assistance
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Page 10
GT724 Installation and Operations Manual
Calibration
Continued
Room Transmit Level Adjustment
Someone in the local room should speak into the microphone at a normal
distance, in a normal voice. The party at the other location should not speak
during the transmit adjustments.
Adjust the ROOM TRANSMIT trim pot [15] (See Figure 16, below.) while
monitoring the ROOM TRANSMIT LED [14]. The ROOM TRANSMIT
LED should be solid green while the person is speaking and extinguish when
the person stops.
Figure 16. GT724 front panel controls
Under normal operating conditions, the ROOM TRANSMIT trim pot [15] is
typically set at a 10 o’clock position or one-fourth open (Figure 17, left).
4 Wire/Video Transmit Level Adjustment
VIDEOCONFERENCING NOTE:
If you are not using the GT724 in four-wire (video) mode, skip to Room Receive
Level Adjustment (next page).
Figure 17. Factory default trim-pot position
Someone in the local room should continue to speak into the microphone
from a normal distance, in a normal voice; the other party should continue to
maintain silence. While the person in the local room speaks, adjust the 4
WIRE/VIDEO TRANSMIT trim pot [19] to match the input level of your
four-wire (video) equipment. The 4 WIRE/VIDEO TRANSMIT LED [18]
should be solid green while the person is speaking and extinguish when the
person stops.
Under normal operating conditions, the 4 WIRE/VIDEO TRANSMIT trim
pot [19] is typically set at the 10 o’clock position or one-fourth open (Figure
17, above).
MULTIPOINT CONFERENCING NOTE:
For applications that will be used in mulitpoint conferencing, it is important to
develop a network standard for your transmit level. All sites should conform to
this level. Gentner Communications recommends a -10dBm level for multipoint
networks.
4 Wire/Video Receive Level Adjustment
Someone in the distant location should speak into their microphone from a
normal distance, in a normal voice. The people in the local room should not
speak during these receive adjustments. While the person speaks, adjust the
4 WIRE/VIDEO RECEIVE trim pot [21] until the 4 WIRE/VIDEO
RECEIVE LED [20] is solid green and just begins to flash red on audio
peaks.
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GT724 Installation and Operations Manual
Page 11
AUDIO PEAK NOTE:
The 4 WIRE/VIDEO RECEIVE LED [20] is the only LED that should be set to
flash red on audio peaks. This level is 6dB below clipping and is the optimum
level for maximum echo cancellation.
Room Receive Level Adjustment
Someone in the distant location should continue to speak into their
microphone from a normal distance, in a normal voice; the local room should
maintain silence.
Internal Power Amp
If you are using the GT724’s internal power amp, adjust the ROOM
RECEIVE trim pot [17] (while the person is speaking) for a comfortable
listening level on the speaker(s).
External Power Amp
If you are using an external power amp, such as the MPAII Mixer/Power
Amplifier, adjust the ROOM RECEIVE trim pot [17] to match the input
level of your external power amp. Then adjust your power-amp level for a
comfortable listening level on the speaker(s).
The ROOM RECEIVE LED [20] should be solid green with receive audio
and extinguish when no audio is present.
Automatic Setup
Once the above settings and adjustments have been completed, the setup
routine must be initiated. For best results, neither the party at the other
location or anyone in the room should speak during the setup-routine noise.
(It will sound like static.) The AES switch [25] should be OFF; the AEC
switch [23] should be ON. The GT724 should be in two-wire (telephone)
mode, four-wire (video) mode or both.
Momentarily press the TELEPHONE [29] and the 4 WIRE/VIDEO [27]
buttons simultaneously. This will transmit a white-noise burst (static) over
the speakers for 25 seconds, or until the GT724 has adapted for maximum
echo cancellation.
During normal conversation, if the AEC LED [22] stays green, no further
adjustments to the AES/AEC switches need be made.
During normal conversation, it is normal for the AEC LED [22] to
occasionally flash red. If the AEC LED turns solid red while the calling
party is speaking at normal levels, contact Gentner Communications for
setup assistance.
The AES (Acoustic Echo Suppression) switch [25] can be used to help
eliminate echo in particularly harsh acoustic environments. However, in
typical operating environments, this feature is not used and should remain in
the OFF position.
READJUSTMENT NOTE:
If you make any additional adjustments or changes on the front panel, or if any
mics or speakers are moved after setup has been completed, initiating the
automatic-setup routine is recommended before operating the GT724.
Technical or Setup Assistance
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Page 12
GT724 Installation and Operations Manual
Calibration
Continued
Volume + and Volume –
These front-panel controls [32, 33] (See Figure 18, below.) should not be
adjusted during calibration. Their use will be described in the Operation
section (next page).
Figure 18. Front panel controls
Front Panel Security
Now that your system has been properly installed, adjusted and calibrated,
and setup is complete, your level settings can be protected from tampering by
sliding the front-panel cover to the left-most position.
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GT724 Installation and Operations Manual
Operation
Page 13
Videoconferencing
Establishing a Videoconference
Videoconferencing systems and networks vary, and can be as diverse as there
are different manufacturers and types of networks used. Your audiovisual
installer/specialist should provide the information necessary to establish your
videoconference using the type of network your equipment utilizes.
Once your conference connection is established through your network, the
GT724 will be engaged and audio will be sent to and received from the other
room by pressing the 4 WIRE/VIDEO button [27] (Figure 18, previous page).
When in use, the associated green LED [26] will light and the red PRIVACY
LED [30] will go out. The audio for your videoconference will be processed
through the GT724, using DSP to provide the clearest audio possible along
with your video transmission.
Terminating a Videoconference
When the videoconference is concluded, press the 4 WIRE/VIDEO button
[27] again. The green LED [26] will go out amd the red PRIVACY LED
[30] will light, indicating the connection is terminated.
Your audiovisual installer/specialist should provide the information necessary
to properly terminate your video transmission, depending on the type of
equipment you are using.
Simultaneous Two-Wire/Four-Wire Mode
When already engaged in a videoconference, make a call using your
telephone set. When the person answers, simply hit the TELEPHONE [29]
button. The telephone call will automatically be included in your
videoconference.
If using RS232 touch tones, it is not necessary to hit the TELEPHONE
button [29]. When using the D serial-port command, the GT724
automatically activates the two-wire (telephone) mode. See Appendix D,
RS232 Touch Tones, Page 24.
To terminate the telephone call, simply press the TELEPHONE button [29]
again. It will not affect your four-wire (video) conference.
VIDEOCONFERENCE TERMINATION NOTE:
You cannot terminate a videoconference while the two-wire (telephone) mode is
engaged. The two-wire (telephone) must be terminated before terminating the
four-wire (video) mode.
Teleconferencing
Answering a Call
An incoming call will ring on the telephone set (the TELEPHONE LED [28]
will flash rapidly during each ring). Answer the call by pressing the
TELEPHONE button [29] on either the front panel or the remote-control
pad. The green TELEPHONE and 4 WIRE/VIDEO LEDs [26, 28] will turn
on and the red PRIVACY LED [30] will turn off. The call may also be
answered on the telephone set and then given to the GT724 by pressing the
TELEPHONE button [29], if you prefer. (See also Auto-Answer/AutoDisconnect Mode, next page.)
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GT724 Installation and Operations Manual
Operation
Continued
Making a Call
Using your telephone set, call someone. After the other party has answered
the call, press the TELEPHONE button [29] (Figure 18a, below). The
TELEPHONE and 4 WIRE/VIDEO LEDs [26, 28] will light and the
PRIVACY LED [30] will turn off. The GT724 takes control of the call and
disables the telephone set. You should now hang up the handset.
Figure 18a. Front panel controls
If using RS232 touch tones, it is not necessary to hit the TELEPHONE
button [29]. When using the D serial-port command, the GT724
automatically activates the two-wire (telephone) mode. See Appendix D,
RS232 Touch Tones, Page 24.
Disconnecting a Call
When you are finished with the call, press the TELEPHONE button [29]
again. The TELEPHONE LED [28] will turn off and the 4 WIRE/VIDEO
LED [26] will remain lit. Press the 4 WIRE/VIDEO button [27] to dim the 4
WIRE/VIDEO LED [28].
Auto-Answer/Auto-Disconnect Mode
In the auto-answer mode, the GT724 will automatically answer telephone
calls after one complete ring, even if already engaged in a four-wire (video)
conference.
To put the GT724 in auto-answer mode, make sure that a Two-wire
(telephone) call is not currently connected. (When not connected, the red
PRIVACY LED [30] will be lit and the green TELEPHONE LED [28] and 4
WIRE/VIDEO LED [26] will be off; or the 4 WIRE/VIDEO LED [26] may
be lit and the red PRIVACY LED [30] and green TELEPHONE LED [28]
will be off). Press and hold the TELEPHONE button [29]. When the
associated LED [28] begins blinking at a slow, steady rate (after
approximately four seconds), release the button. As long as the LED is
blinking, the GT724 will remain in auto-answer/auto-disconnect mode. The
PRIVACY LED [30] will remain lit, unless active in four-wire (video) mode.
When a two-wire (telephone) call is auto-disconnected, the 4 WIRE/VIDEO
LED [26] will remain lit. Press the 4 WIRE/VIDEO button [28] to switch it
off.
AUTO-ANSWER/AUTO-DISCONNECT NOTE:
This mode may not function as described with some PBX systems. The difficulty
with the auto-answer mode may be caused by ring timing. Auto-disconnect
requires loop drop or loop reversal to function. Contact your telephone company
for this signaling.
Terminating Auto-Answer/Auto-Disconnect Mode
To take the GT724 out of auto-answer/auto-disconnect mode, make sure the
GT724 is not currently on a call (the PRIVACY LED [30] should be lit and
the TELEPHONE LED [28] should be blinking slowly). Press and hold the
TELEPHONE button [29]. Release when the TELEPHONE LED [28] turns
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Page 15
off.
Privacy
If you wish to mute your conversation (so the remote parties cannot hear
you), press the PRIVACY button [31]. The red PRIVACY LED [30] will
light up; however, you will still be able to hear the other locations. When
you want to resume two-way communication with the other parties, press the
PRIVACY button [31] again. The PRIVACY LED [30] will turn off, reestablishing two-way communication with your parties.
PRIVACY NOTE:
When using the PRIVACY button [31], both the two-wire (telephone) and fourwire (video) send audio is muted.
Increasing Listening Volume
If the audio on the speakers is not loud enough, press and hold the
VOLUME + button [33] until the desired listening level is reached. This
does not adjust the level of the audio the other location hears.
Decreasing Listening Volume
If the audio on the speakers is too loud, press and hold the VOLUME –
button [32] until the desired listening level is reached. This does not adjust
the level of the audio that the other location hears.
Restoring Listening Volume to Default
To restore volume levels to a nominal, mid-range setting, press and hold the
VOLUME + [33] and VOLUME – buttons [32] simultaneously.
VOLUME DEFAULT NOTE:
At the conclusion of each conference, the volume levels are automatically
restored to the nominal, mid-range setting.
Remote Control Option
The optional Gentner Remote Control contains six essential operational
buttons: 4 Wire/Video, Telephone, Privacy, Phone Add, Volume + and
Volume –. The 4 Wire/Video, Telephone and Privacy buttons operate exactly
as their respective buttons on the GT724’s front panel.
FOUR-WIRE NOTE:
If the GT724 is not in the four-wire (video) mode prior to the two-wire
(telephone) connection, the 4 Wire Video LED on the remote control will also
light when the Telephone or Phone Add buttons are pressed.
The phone-add feature is activated by pressing the Phone Add or Telephone
buttons on the remote control or TELEPHONE button [29] on the GT724.
PHONE ADD BUTTON NOTE:
The Phone Add button and the Telephone button on the remote control perform
the same function as the TELEPHONE button [29] on the GT724 front panel.
The 4 Wire/Video, Telephone, Privacy and Phone Add buttons each contain
their respective LEDs to graphically indicate current operation mode. These
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GT724 Installation and Operations Manual
Operation
Continued
four buttons are push-on/push-off in operation.
AUTO-ANSWER/AUTO-DISCONNECT NOTE:
This function can be activated from the remote control as per the front-panel
controls (Page 14). However, the Phone Add button cannot activate/deactivate
the auto-answer/auto-disconnect function.
The Volume + and Volume – buttons will incrementally increase/decrease the
remote parties’ volume level, in the same manner as using the respective
buttons on the GT724 front panel.
Emergency Restoration
As long as power is maintained, your system will maintain all information
the GT724 has “learned” about your room environment.
Following a power failure, the GT724 will reset itself to factory default
settings. On first connection of two-wire (telephone) or four-wire (video), a
three-second white noise (static) burst will automatically be emitted to
quickly read the room and make internal settings for echo-elimination.
If the system is still unstable or echo is present, a full setup routine should be
initiated to set the system to optimal operation. Momentarily press the
TELEPHONE [29], 4 WIRE/VIDEO [27] buttons simultaneously (Figure
18b, below). AEC/AES switches and volume should be kept in the position
set prior to the outage. The receive volume level will reset to nominal levels.
Two-wire (telephone) or four-wire (video) operation will need to be
reinitiated by pressing the required button (LED will light). The telephone
call will need to be redialed, when using the telephone mode.
Figure 18b. Front panel controls
FOUR-WIRE (VIDEO) NOTE:
If continual power failures occur, your GT724 can be programmed to
automatically retrain when power is restored. To do this, connect pins 8 and 9
together on the REMOTE [4] connector (Figure 3, Page 6). The system will
power up in four-wire (video) mode, train for 25 seconds, and remain in the fourwire (video) mode. In conjunction with pin 8, if you want to lock the GT724 in
the four-wire (video) mode continually, connect pins 15 and 9 together on the
REMOTE connector [4]. This mode locks the unit into four-wire (video) mode
and disables the 4 WIRE/VIDEO button [27].
When Not in Use
When the GT724 is not in use, the red Privacy LED [30] will remain lit, and
the green TELEPHONE LED [26] and 4 WIRE/VIDEO LED [28] will be off
(if in auto-answer mode, the TELEPHONE LED [26] will be blinking).
POWER NOTE:
Power should be maintained to the unit at all times.
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Two-Wire (Telephone)
Teleconferencing
The GT724 provides all connections necessary to perform point-to-point
audioconferencing over a standard telephone line. When open microphones and
speakers are used at each location, two GT724s should be used (See Figure 19,
below; disregard CODEC connection.), one at each location, to achieve
maximum audio quality. The two locations may be either in the same building or
at distant sites. Only one GT724 is required when the distant location is using a
handset or speakerphone. If you are conferencing room-to-room, and you want to
maintain full-duplex, you must use one GT724 in each room.
Figure 19. Two-GT724 connection
GT724 COMPATIBILITY NOTE:
The GT724 is compatible with most other manufacturer’s teleconferencing
equipment; however, systems with full-duplex capability are recommended.
Four-Wire (Video)
Teleconferencing
The GT724 can be used to provide full-duplex audio for videoconferencing
applications. One GT724 is required to interface to a video CODEC or
transceiver system at each location.
Figure 19 (above) illustrates a two-GT724 connection in a videoconferencing
scenario. If using two GT724 for four-wire (video) conferencing only, disregard
the telephone applications. If your application occasionally uses telephone (two
wire) conferencing, make all connections shown
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GT724 Installation and Operations Manual
Bridging
Multiple Calls
Telephone bridge services, such as 1-800 LETS MEET, are available to connect
multiple remote sites to your GT724 conference. The bridging service can
connect all callers together then direct them to one GT724. The number of
distant locations that can be conferenced together is dependent upon the
telephone bridge service used. Contact 1-800 LETS MEET at 1-800 LETS MEET
for more information. 1-800 LETS MEET’s bridge service offers the best audio
quality possible when bridging your sites together.
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GT724 Installation and Operations Manual
Specifications
Page 19
GT724
Dimensions
19"/48.3cmW x 1.75"/4.45cmH x 10"/25.4cmD
Weight
10 lbs./4.5 kg dry
13 lbs./5.9 kg shipping
Connectors
POWER:
Auto-adjusting power module
REMOTE:
DB15 female
ROOM TRANSMIT 3-pin female XLR; balanced bridging >20k W
INPUT:
input impedance; +4dBu nominal level, adjustable
ROOM RECEIVE
OUTPUT:
3-pin male XLR; balanced; 50 W (designed to drive
> 600 W inputs); +4dBm nominal level, adjustable
4 WIRE TRANSMIT 3-pin male XLR; balanced; 50 W (designed to drive
OUTPUT:
> 600 W inputs); -10dBm nominal level, adjustable
4 WIRE RECEIVE
INPUT:
3-pin female XLR; balanced, bridging >20k W
input impedance; -10dBu nominal level, adjustable
RECORD OUTPUT: Phono connector; unbalanced; 1k W output impedance
(designed to drive > 10k W inputs); -10dBu nominal
level
PLAYBACK INPUT: Phono connector; 10k W input impedance; -10dBu
nominal, adjustable
RS232:
DB9 female
TELCO LINE/SET: RJ11C
Power Requirements
85–240Vac; 50/60Hz; (Fuse) 2 amp 250Vac, Slo Blo type
Frequency Response
50Hz to7kHz +1dB in four-wire (video) mode; 300 to 3.4kHz +1dB with 6dB
pre-emphasis on transmit in two-wire (telephone) mode
Operating Temperature
32–100° F
Specifications are subject to change without notice.
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GT724 Installation and Operations Manual
Warranty
Gentner Communications Corporation (Manufacturer) warrants that this product is free of defects in both materials and
workmanship. Should any part of this equipment be defective, the Manufacturer agrees, at its option, to:
A. Repair or replace any defective part free of charge (except transportation charges) for a period of one
year from the date of the original purchase, provided the owner returns the equipment to the Manufacturer at the
address set forth below. No charge will be made for parts or labor during this period;
B. Furnish replacement for any defective parts in the equipment for a period of one year from the date of original
purchase. Replacement parts shall be furnished without charge, except labor and transportation.
This Warranty excludes assembled products not manufactured by the Manufacturer whether or not they are
incorporated in a Manufacturer product or sold under a Manufacturer part or model number.
THIS WARRANTY IS VOID IF:
A. The equipment has been damaged by negligence, accident, act of God, or mishandling, or has not been operated in
accordance with the procedures described in the operating and technical instructions; or,
B. The equipment has been altered or repaired by other than the Manufacturer or an authorized service representative
of the Manufacturer; or,
C. Adaptations or accessories other than those manufactured or provided by the Manufacturer have been made or
attached to the equipment which, in the determination of the Manufacturer, shall have affected the performance, safety
or reliability of the equipment; or,
D. The equipments original serial number has been modified or removed.
NO OTHER WARRANTY, EXPRESS OR IMPLIED, INCLUDING WARRANTY OF MERCHANTABILITY OR
FITNESS FOR ANY PARTICULAR USE, APPLIES TO THE EQUIPMENT, nor is any person or company authorized
to assume any warranty for the Manufacturer or any other liability in connection with the sale of the Manufacturer's
products.
Manufacturer does not assume any responsibility for consequential damages, expenses, or loss of revenue or property,
inconvenience, or interruption in operation experienced by the customer due to a malfunction in the purchased
equipment. No warranty service performed on any product shall extend the applicable warranty period.
In case of unsatisfactory operation, the purchaser shall promptly notify the Manufacturer at the address set forth below
in writing, giving full particulars as to the defects or unsatisfactory operation. Upon receipt of such notice, the
Manufacturer will give instructions respecting the shipment of the equipment, or such other matters as it elects to
honor this warranty as above provided. This warranty does not cover damage to the equipment during shipping and the
Manufacturer assumes no responsibility for such damage. All shipping costs shall be paid by the customer.
This warranty extends only to the original purchaser and is not assignable or transferable.
Gentner Communications Corporation, 1825 Research Way, Salt Lake City, Utah 84119
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GT724 Installation and Operations Manual
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FCC Part 15
Compliance
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 when the
equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency
energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to
radio communications. Operation of this equipment in a residential area is likely to cause harmful interference, in
which case the user will be required to correct the interference at his/her own expense.
Changes or modifications not expressly approved by Gentner Communications Corporation could void the user’s
authority to operate the equipment.
FCC Part 68
Compliance
FCC Registration Number: FBIUSA21442BRN
The Ringer Equivalence Number (REN) is 1.1B
A label containing, among other information, the FCC registration number and Ringer Equivalence Number (REN) for
this equipment is prominently posted on the top plate, near the rear of the equipment. If requested, this information
must be provided to your telephone company.
USOC Jacks: This device uses RJ11C and RJ21X terminal jacks.
The REN is used to determine the quantity of devices which may be connected to the telephone line. Excessive RENs
on the telephone line may result in the devices not ringing in response to an incoming call. In most, but not all areas,
the sum of the RENs should not exceed five (5). To be certain of the number of devices that may be connected to the
line, as determined by the total RENs, contact the telephone company to obtain the maximum RENs for the calling
area.
If this equipment causes harm to the telephone network, the telephone company will notify you in advance that
temporary discontinuance of service may be required. If advance notice is not practical, the telephone company will
notify the customer as soon as possible. Also, you will be advised of your right to file a complaint with the FCC if you
believe it is necessary.
The telephone company may make changes in its facilities, equipment, operations, or procedures that could affect the
operation of the equipment. If this happens, the telephone company will provide advance notice for you to make the
necessary modifications in order to maintain uninterrupted service.
If you experience problems with this equipment, contact Gentner Communications Corporation, 1825 Research Way,
Salt Lake City, Utah 84119, or by phone at (801) 975-7200 for repair and warranty information. If the trouble is
causing harm to the telephone network, the telephone company may request you remove the equipment from the
network until the problem is resolved.
No user serviceable parts are contained in this product. If damage or malfunction occurs, contact Gentner
Communications for instructions on its repair or return.
This equipment cannot be used on telephone company provided coin service. Connection to Party Line Service is
subject to state tariffs.
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GT724 Installation and Operations Manual
IC Compliance
NOTICE: The Industry of Canada label identifies certified equipment. This certification means that the equipment
meets certain telecommunications network protective operational and safety requirements. The Department does not
guarantee the equipment will operate to the 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 (telephone extension cord). The customer should be aware that 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 Gentner
Communications. 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.
Users should ensure for their own protection 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.
The Ringer Equivalence Number (REN) is 1.1
IC Certification Number : 19706306A
Safety
Information
CAUTION: For use only with certified telecommunication equipment.
ATTENTION: Pour utilisation seulement avec du materiel de telecommunications certifie de marque.
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BABT Recording
Requirements
This condition applies in circumstances where you wish to use telecommunications apparatus comprised in or
connected to your system to record, silently monitor or intrude into live-speech telephone calls. (It does not apply
where the apparatus in question is not telecommunications apparatus; i.e. is not apparatus that had been constructed or
adapted for use in transmitting or receiving telecommunications messages.) Silent monitoring is the establishment of a
receive-only transmission path to a third terminal, enabling a third party to hear the call. Instrusion is the
establishment of a bothway speech transmission to another terminal enabling a third party to hear and be heard by at
least one of the other parties to the call. The condition does not apply to the monitoring of telephone calls for a systems
control or diagnostic purposes where the meaningful content of the call itself is monitored.
This condition provides that you should make every reasonable effort to inform all parties to a call that it may or will be
recorded, silently monitored or intruded into. The particular means by which you choose to do this are not specified in
the condition. Acceptable options, depending on circumstances, might include warning tones, prerecorded messages,
spoken warnings by the operator or written warnings included in publicity material, telephone directories, contracts,
terms of business, staff notices, etc. It may not always be possible to warn first-time callers with whom you have had
no previous contact but what is important is that you have a systemic procedure in place which provides the necessary
information wherever this is a realistic possibility.
For recording and silent monitoring, this condition recognises two forms of warning: a written notice before the call or
a warning during the call itself. Both warnings should also inform all parties to a call why it is being recorded or
silently monitored. In the case of intrusion, a warning before the intrusion takes place is sufficient as both parties will
become aware that a third party has joined their conversation.
This condition does not specify the detail of how these forms of warning should be given. A written statement included
in any of the following — contractural terms, conditions of employment, publicity material, staff notices, telephone
directory entries — would be a possible method.
The essential point is that the equipment user must be able to demonstrate that a determined attempt has been made to
reach prospective callers; as an illustration, we would expect any warning included in a company’s publicity material to
be presented in such a way that it would not be missed by anyone looking for that company’s telephone number(s). A
warning which is not clearly visibly would fail to meet this requirement.
Where the warning is to be given during the call itself, the possibilities include a recorded message at the beginning of
the call or a spoken message at any time during the conversation.
You should also maintain a record of the means by which callers have been warned which the Director may request
sight of. This does not mean that you have to log each phone call; rather, that should a dispute arise, it will be possible
for you to show from records how callers were being made aware at the time.
This condition does not apply where apparatus is being used for the purpose of law enforcement or in the interests of
national security or to calls involved the national Emergency Organisations. It also provides that other licensees may
be excluded, by means of a Director’s consent, where there are compelling factors that outweigh the normal expectation
of privacy. Such factors might apply where security is a consideration or in the case of specialised users such as
helplines. In accordance with Section 19 of the Telecommunications Act of 1984, these consents will be entered on a
register open to public inspection.
This condition attempts to secure objectives similar to those which weere previously achieved through an approval
requirement that equipment capable of recording, silently monitoring or intruding into telephone conversations should
emit warning tones as these operations take place. The removal of warning tones was permitted by an OFTEL General
Variation provided that an alternative form of warning was given. The expectation is that procedures complying with
the General Variation should, generally, also meet the requirements of this condition.
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GT724 Installation and Operations Manual
Appendix A:
Glossary
Throughout this manual, you may notice some unfamiliar terms. Some of these terms and how they relate to the
GT724 appear below.
AEC
Acoustic echo cancellation.
AES
Acoustic echo suppression
Digital Echo Cancellation
The GT724 digitally subtracts acoustic echo from the audio being returned to the
caller. The GT724 digitally eliminates both direct and indirect acoustic echoes,
making the conference much more intelligible.
Full-Duplex Operation
Both locations can speak simultaneously without interruption, because the GT724
does not use switching to cut off either the transmit or receive audio signals. This
produces full-duplex operation.
Digital Gain Processing
The GT724 uses special digital gain processing techniques to maintain consistent
audio levels within the room. Receive volume levels will be maintained
consistently, evenwhen changes occur in the other room, or telephone line
conditions change.
PBX
Private branch exchange. This is a common form of business telephone system.
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Page 25
Appendix B: Connector
Pinouts
Table 1. Remote Control DB15 Connector Pinouts
Pin Number
1
2
3
4
5
6
7
8
Control
Ground
Two-wire audio switch
Four-wire audio switch
Privacy switch
Phone add switch
Volume up
Volume down
Four-wire mode
Pin Number
9
10
11
12
13
14
15
Control
Ground
Two-wire lamp
Four-wire lamp
Privacy lamp
Phone add lamp
Not used
Four-wire lock
Pin Number
6
7
8
9
Control
DSR
No connection
CTS
No connection
Table 2. RS232 DB9 Connector Pinouts
Pin Number
1
2*
3*
4
5*
Control
DCD
Transmit
Receive
DTR
Ground
* Required for computer or remote control
Table 3. Telephone Set and Line Connections
1
2
3
4
5
6
Telephone Set
No Connection
A-lead closure
Ring
Tip
A-lead closure
No connection
1
2
3
4
5
6
Telephone Line
No Connection
A-lead closure
Tip
Ring
A-lead closure
No Connection
Table 4. DB9 Microphone Connector Pinouts
Pin Number
1
2
3
4
5
Control
Mic 1+
Mic 1Mic 2+
Mic 2Mic 3+
Pin Number
6
7
8
9
Control
Mic 3Ground
Ground
Ground
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GT724 Installation and Operations Manual
Appendix C: Available
Options
Accessory
Tabletop Omni Microphone
Tabletop Unidirectional Microphone
Delta Microphone
Wall Mount Speaker
Mixer/Power Amplifier
Remote Control
Appendix D: Serial Port
Commands
The RS232 serial port will accept serial commands. The commands provide the
same control as the front-panel switches, except that the serial commands will not
control either the AEC or the AES switches.
Gentner Part Number
910-103-148
910-103-158
910-103-333
910-103-010
910-101-001
910-110-100
RS232 Serial Port Protocol
9600 baud, 8 bits, 1 stop bit, no parity
Teleconferencing Interface
Gentner Communications Corporation © 1993
When the serial port is connected to a computer, the information in Figure 20,
(left) will be displayed on the screen on power-up:
Ports Initialized
SERIAL PORT NOTE:
Placing 3 milliseconds of character spacing between commands will reduce the
chance of missed commands. It is also best to wait for the GT724 to
acknowledge a command before going on to the next one.
POC vx.x
RAM
OK
CODEC OK
GT724
INTERRUPTS $Revision: x.xx$
INTERRUPTS SETUP $Revision: x.xx$
BACKGROUND $Revision: x.xx$
GT724 MONITOR $Revision: x.xx$
Figure 20. GT724 power-up message
The GT724 is now in the serial command mode. The GT724 serial commands
taken in this mode are shown in Table 5 (below), as well as all telephone-keypad
digits (0–9), the * and # keys (for voice-mail/pager use; see RS232 Touch-Tone
Dialing, next page). These commands are designed to allow users to control the
GT724 through the serial port.
The basic structure of the serial commands are one or two letters with a digit
following the letters. The two letters identify the command type. The digit or
lack of a digit tells the GT724 what to do with the current command.
Table 5. GT724 Serial Port Commands
Function
Auto Answer
Four-wire (video)
Privacy
Setup
Volume down
Command
AA
4W
P
S
L-
Function
Dialing
Phone Add
Ring acknowledgment
Two-wire (telephone)
Volume up
Command
Dx
PA
RING
TE
L+
SERIAL COMMAND NOTE:
All commands are not complete until you hit ENTER.
Technical or Setup Assistance
Telephone: 800.945.7730 (USA) or 801.975.7200 (worldwide) • Worldwide Web @ http://www.gentner.com
GT724 Installation and Operations Manual
Page 27
Appendix D:
Continued
Two-Wire (Telephone)
The TE command has the same function as the two-wire audio switch. It connects or disconnects the GT724 in
two-wire mode.
TE1 <CR>
Connects the GT724 in two-wire mode.
TE0 <CR>
Disconnects the GT724 from two-wire mode.
TE <CR>
Returns the two-wire connect state.
The GT724 responds, TE1 <CR> (if connected) or TE0
<CR> (if not connected).
The GT724 responds, TE0 <CR>.
The GT724 responds, TE1 <CR> if connected or TE0
<CR> (if not connected).
Four-Wire (Video)
The 4W1 command has the same function as the four-wire video switch. It connects or disconnects the GT724 in
four-wire mode.
4W1 <CR>
Connects the GT724 in four-wire mode.
4W0 <CR>
Disconnects the To from four-wire mode.
4W <CR>
Returns the four-wire connect state.
The GT724 responds, 4W1 <CR> (if connected) or 4W0
<CR> (if not connected).
The GT724 responds, 4W0 <CR>.
The GT724 responds, 4W1 <CR> (if connected) or 4W0
<CR> (if not connected).
RS232 Touch-Tone Dialing
To dial touch tones through the RS232 port, send Dx (x stands for a single button on a telephone keypad). All
digits on a standard telephone keypad (0–9) are available for use when issuing tones through the RS232 port, as
well as the * and # keys, for use with voice mail and pagers.
Dx <CR>
Sends the first digit.
The GT724 automatically activates two-wire (telephone)
mode and responds, Dx <CR>.
OR
Dxxxxxxxxxxx <CR>
Sends entire phone number as a string.
RING <CR>
GT724 receives a ring at the dialed-up location.
The GT724 automatically activates the two-wire
(telephone) mode and responds, Dxxxxxxxxxxx <CR>.
The GT724 responds, RING <CR>.
TOUCH-TONE NOTE:
Before sending additional commands, wait for the GT724 to respond. Also, if you require a pause in your dial-out
string (for the telephone to grab an outside line, etc.) enter a comma (,). Example: D9,1234567 <CR>. The “,” is
read by the GT724 as a two-second pause.
Technical or Setup Assistance
Telephone: 800.945.7730 (USA) or 801.975.7200 (worldwide) • Worldwide Web @ http://www.gentner.com
Page 28
GT724 Installation and Operations Manual
Appendix D:
Continued
Phone Add
To put the GT724 in phone-add mode, send
PA1 <CR>
Enables phone add.
The GT724 responds, PA1 <CR>.
PA0 <CR>
Disables phone add.
The GT724 responds, PA0 <CR>.
PA <CR>
Returns the current phone-add status.
The GT724 responds, PA1 <CR> (if phone-add active) or
PA0 <CR> (if phone-add inactive).
Privacy
The GT724’s privacy mode will work if the GT724 is connected to either the telephone lines (two wire) or the
four-wire interface. To enable the privacy through the serial port, send the following characters:
P1 <CR>
Enables privacy mode.
The GT724 responds, P1 <CR>.
P0 <CR>
Disables privacy mode.
The GT724 responds, P0 <CR>.
P <CR>
Returns the current status of privacy.
The GT724 responds, P1 <CR> (if privacy is enabled) or
P0 <CR> (if privacy is disabled).
Volume Up and Volume Down
The volume up command us initiated by sending the following characters:
L+ <CR>
Increases the volume level.
The GT724 responds, L+ <CR>.
L- <CR>
Decreases the volume level.
The GT724 responds, L- <CR>.
Volume Status
The GT724 will return the volume status by sending the following characters:
L <CR>
Returns the current volume level.
The GT724 responds, L+1 <CR> (for example) if the
volume level is up one decibel, or L-3 <CR> (for
example) is the volume level is down three decibels.
Auto Answer
The GT724 is put in auto-answer mode by sending the following characters through the serial port:
AA1 <CR>
Enables auto answer.
The GT724 responds, AA1 <CR>.
Technical or Setup Assistance
Telephone: 800.945.7730 (USA) or 801.975.7200 (worldwide) • Worldwide Web @ http://www.gentner.com
GT724 Installation and Operations Manual
Page 29
Auto Answer continued
AA0 <CR>
Disable auto answer.
The GT724 responds, AA0 <CR>.
AA <CR>
Returns the current auto answer state.
The GT724 responds, AA1 <CR> (if auto answer
enabled) or AA0 <CR> (if auto answer disabled).
Setup
To put the GT724 into setup mode, send
S1 <CR>
Puts the GT724 into setup mode.
The GT724 responds, S1 <CR>.
SETUP NOTE:
The GT724 must be connected in four-wire (video) or two-wire (telephone) mode first.
S0 <CR>
Takes the GT724 out of setup mode.
S <CR>
Returns the current status of setup mode.
The GT724 responds, S0 <CR>.
The GT724 responds, S1 <CR> (if in setup mode) or S0
<CR> (if not in setup mode).
SETUP EXIT NOTE:
The setup training will timeout after 25 seconds.
Status
A special command returns the entire status of the GT724 in one command. The character string for the command
is
ST <CR>
Returns the entire GT724 status.
The GT724 responds in the following order:
AAx
Sx
Lxx
Px
PAx
TEx
4Wx
Technical or Setup Assistance
Telephone: 800.945.7730 (USA) or 801.975.7200 (worldwide) • Worldwide Web @ http://www.gentner.com
Page 30
GT724 Installation and Operations Manual
Appendix E: PC Command
Quick Reference
TE <CR>
TE1 <CR>
TE0 <CR>
4W <CR>
4W1 <CR>
4W0 <CR>
Dx <CR>
RING <CR>
P <CR>
P1 <CR>
P0 <CR>
L <CR>
L+ <CR>
L- <CR>
AA <CR>
AA1 <CR>
AA0 <CR>
S <CR>
S1 <CR>
S0 <CR>
PA <CR>
PA1 <CR>
PA0 <CR>
ST <CR>
Return two-wire connect status
Connect in two-wire
Disconnect two-wire
Return four-wire connect status
Connect in four wire
Disconnect in four wire
Dial RS232 touch tones
Response when GT724 acknowledges a ring
Return privacy status
Enables privacy
Disable privacy
Return current volume level
Increase volume level
Decrease volume level
Return current auto answer status
Enable auto answer
Disable auto answer
Return current setup status
Enable setup
Disable setup
Return current phone add status
Enable phone add
Disable phone add
Return all above status
Technical or Setup Assistance
Telephone: 800.945.7730 (USA) or 801.975.7200 (worldwide) • Worldwide Web @ http://www.gentner.com
GT724 Installation and Operations Manual
Page 31
Appendix F: GT724
Block Diagram
Technical or Setup Assistance
Telephone: 800.945.7730 (USA) or 801.975.7200 (worldwide) • Worldwide Web @ http://www.gentner.com
Page 32
GT724 Installation and Operations Manual
GT724 Notes
Technical or Setup Assistance
Telephone: 800.945.7730 (USA) or 801.975.7200 (worldwide) • Worldwide Web @ http://www.gentner.com
“Our vision is to provide our customers with
the total audio solution for conferencing.”
GENTNER COMMUNICATIONS CORPORATION
Sales and Technical Assistance
1825 Research Way
Salt Lake City, Utah 84119
Toll Free 800-945-7730
Telephone 801-975-7200
FAX 801-977-0087
FAX-On-Demand 800-695-8110
Worldwide Web Page @ http:\\www.gentner.com
Gentner Part No. 800-114-001 (Rev. 1.00)
1
2
3
4
5
6
CONTROL I/O
D
+V
+15V
-V
-15V
+VL
+5L
FP_CTRL[0..16]
LEVEL_LED[0..11]
FP_CTRL[0..16]
LEVEL_LED[0..11]
LINE_STATUS
TELCO_RELAY
4_WIRE
2_WIRE
FP_CTRL13
FP_CTRL16
FP_CTRL12
FP_CTRL7
FP_CTRL11
FP_CTRL5
FP_CTRL10
FP_CTRL3
FP_CTRL9
FP_CTRL1
FP_CTRL8
RECEIVE_GREEN
RECEIVE_RED
TRANSMIT_GREEN
TRANSMIT_RED
IO_SEL
+15V
J8
IN14
IN15
PHONE_ADD_OFF
PHONE_ADD_ON
IN[0..17]
D[0..23]
8
15
7
14
6
13
5
12
4
11
3
10
2
9
1
VOLUME_DOWN
AUX_CTRL
VOLUME_UP
PHONE_ADD_REMOTE
PHONE_ADD_SWITCH
PRIVACY_REMOTE
PRIVACY_SWITCH
4_WIRE_CONN_REMOTE
4_WIRE_SWITCH
2_WIRE_CONN_REMOTE
2_WIRE_SWITCH
+5L
REMOTE CONTROL
D
J11
1
2
3
4
5
6
POWER CONNECTOR
DB15
NOT STUFFED
J9
MASCON, 6 pin
-15V
UTI_IO.SCH
TELCO BOARD CONN.
COMM3
COMM1
COMM0
DCD
DSR
TX
COMM4
COMM2
COMM5
RX
CTS
DTR
1
6
2
7
3
8
4
9
5
RS232 PORT
FIR FILTERS
DB9
D[16..23]
A[0..8]
CTRL[0..3]
J10
1
2
3
4
5
6
7
8
9
10
+5L
ROOM I/O
TELCO AND 4 WIRE I/O
4_WIRE
2_WIRE
TRAN_TELCO
RECV_TELCO
FIR_SEL
FIR_START
FIR_CLK
MASCON, 10 pin
UTI_FIRS.SCH
C
DIGITAL PROCESSING
C53
.01UF
TX_IN_POT
TX_IN_TAP
TRAN_IN_POT
TRAN_IN_TAP
FIR_CLK
FIR_START
FIR_SEL
*
R10
2K
J29
TX_FROM_GT
RX_TO_GT
NULL SECTION
2
1
GT CONNECTOR
MASCON, 2 PIN
CTRL[0..3]
A[0..8]
D[0..23]
IN[0..17]
J4
PLAYBACK INPUT
C
RX_OUT_POT
RX_OUT_TAP
RECV_OUT_POT
RECV_OUT_TAP
J5
PLAYBACK_IN
RECORD OUTPUT
RECORD_OUT
IO_SEL
PHONO JACK
PHONO JACK
COMM[0..5]
RECV_TO_CODEC
TRAN_FROM_CODEC
CALLER_IN
SEND_OUT
COMM[0..5]
CALLER_OUT
SEND_IN
RECV_FROM_CODEC
TRAN_TO_CODEC
UTI_DIG.SCH
2
3
1
RECEIVE INPUT
XLR
RECV_IN_+
RECV_IN_RECV_IN_SHIELD
2
3
1
TRAN_IN_+
TRAN_IN_TRAN_IN_SHIELD
TRANSMIT INPUT
J7
4
4
J2
XLR
B
2
3
1
XLR
TRANSMIT OUTPUT
TRAN_OUT_+
TRAN_OUT_-
B
2
3
1
RECV_OUT_+
RECV_OUT_-
AUDIO LEVEL DETECT
RECEIVE OUTPUT
J6
TRAN_PEAK_OUT
TRAN_PRES_OUT
RECV_PEAK_OUT
RECV_PRES_OUT
TRAN_SAMPLE_IN
RECV_SAMPLE_IN
4
4
J1
NOT STUFFED
XLR
TRAN_SAMPLE_OUT
RECV_SAMPLE_OUT
DETLEVEL.SCH
5
9
4
8
3
7
2
6
1
RECV_OUT_BRIDGE_2
RECV_OUT_BRIDGE_1
RX_IN_POT
RX_IN_TAP
RECV_IN_POT
RECV_IN_TAP
TX_OUT_POT
TX_OUT_TAP
TRAN_IN_BRIDGE_2
TRAN_OUT_POT
TRAN_OUT_TAP
TRAN_IN_BRIDGE_1
J3
DB9
P_ADD
P_ADD
TAPE
FONEADD_IN
FONEADD_OUT
TAPE
4_WIRE_A
2_WIRE_A
4_WIRE_A
2_WIRE_A
TRAN_RECORD_OUT
TRAN_RECORD_IN
ROOMIO.SCH
REMOTEIO.SCH
WC
A
RX_IN_POT
TX_OUT_TAP
TX_OUT_POT
TX_IN_TAP
TX_IN_POT
10
9
8
7
6
5
4
3
2
1
RX_IN_TAP
RX_OUT_POT
RX_OUT_TAP
FRONT PANEL AUDIO
LEVEL_LED0
LEVEL_LED2
LEVEL_LED4
LEVEL_LED6
LEVEL_LED8
LEVEL_LED10
FP_CTRL0
FP_CTRL2
FP_CTRL4
FP_CTRL6
FP_CTRL14
FP_CTRL12
SEND_IN_GN
SEND_OUT_GN
CALLER_IN_GN
CALLER_OUT_GN
AEC_GN
AES_GN
2_WIRE_CONN
4_WIRE_CONN
PRIVACY
PHONE_ADD
AEC_SWITCH
VOLUME_UP
1 J19
3
5
7
9
11
13
15
17
19
21
23
25
2
4
6
8
10
12
14
16
18
20
22
24
26
SEND_IN_RD
SEND_OUT_RD
CALLER_IN_RD
CALLER_OUT_RD
AEC_RD
AES_RD
2_WIRE_SWITCH
4_WIRE_SWITCH
PRIVACY_SWITCH
PHONE_ADD_SWITCH
AES_SWITCH
VOLUME_DOWN
LEVEL_LED1
LEVEL_LED3
LEVEL_LED5
LEVEL_LED7
LEVEL_LED9
LEVEL_LED11
FP_CTRL8
FP_CTRL9
FP_CTRL10
FP_CTRL11
FP_CTRL15
FP_CTRL13
MASCON, 10 pin
CONTROL NO.
GENTNER COMMUNICATIONS CORP
1825 RESEARCH WAY
SALT LAKE CITY, UTAH 84119
THIS DOCUMENT CONTAINS
INFORMATION PROPRIETARY
TO GENTNER COMMUNICATIONS CORPORATION AND
MAY NOT BE COPIED IN
WHOLE OR IN PART WITHOUT THE AUTHORIZATION
OF GENTNER COMMUNICATIONS CORPORATION.
DIMENSIONS IN INCHES
NOT TO SCALE
J12
FRONT PANEL CONTROL
A
GT724 MOTHERBOARD BLOCKS
Size
Orcad C
Scale
FCSM No.
DWG No.
720-114-001
Rev
1.2
Sheet
1 of 7
1
BRIDGE
2
3
4
5
6
1
2
3
4
5
6
+5L
+15V
+5L
C111
.1uF
+
6
L10
FB
SAMP_MODE
DIG CODEC
+VL
C112
.1uF
+
.1uF
C114
.1uF
C123
.1uF
C132
.1uF
1
C104
10uF
S
C113
.1uF
C108
.1uF
C115
.1uF
IN15
IN14
C106
SAMP_MODE
IN13
IN16
IN17
8
7
6
5
4
C105
1000PF
RP1C
47K
RP1G
IN12
IN11
8
9
IN10
IN9
IN8
1
2
5
IN7
IN6
IN5
IN4
IN3
IN2
IN1
IN0
11
14
15
16
19
20
22
25
PB14/HACK*
PB13/HREQ*
PB12/HEN*
PB11/HR/W*
PB10/HA2
PB9/HA1
PB8/HA0
1
1
1
1
PB7/H7
PB6/H6
PB5/H5
PB4/H4
PB3/H3
PB2/H2
PB1/H1
PB0/H0
IN[0..17]
B
RP10I
10
/ds
1
RP10F
7
D23
1
RP11G
8
D15
1
9
D7
9
/rd
1
4.7K
RP10E
6
D22
1
4.7K
RP11F
7
D14
1
4.7K
RP8G
8
D6
1
4.7K
RP10G
8
/wr
1
4.7K
RP10D
5
D21
1
4.7K
RP11E
6
D13
1
4.7K
RP8F
7
D5
1
4.7K
RP10C
4
D20
1
4.7K
RP11D
5
D12
1
4.7K
RP8E
6
D4
1
4.7K
RP10B
3
D19
1
4.7K
RP11C
4
D11
1
4.7K
RP8D
5
D3
1
4.7K
RP10A
2
D18
1
4.7K
RP11B
3
D10
1
4.7K
RP8C
4
D2
1
4.7K
RP11I
10 D17
1
4.7K
RP11A
2
D9
1
4.7K
RP8B
3
D1
1
4.7K
RP11H
9
1
4.7K
RP8I
10 D8
1
4.7K
RP8A
2
D0
FSTRT
CONTROL SIGNALS
IO_CS
IO_SEL
D16
4.7K
D[0..23]
CTRL[0..3]
A[0..8]
4.7K
RP8H
6
1
U18
1
7
2
3
STROBE
RP1I
47K
WATCHDOG
4MHZ
14
10K
C
+5L
/RESET
PBR
ST
TD
TOL
5
RST
6
RST
DS1232
C110
.1uF
+5L
+5L
C129
+5L
C128
.1uF
45
43
2
15
12
+5L
RP9D
10K
+5L
4.7K
RP10H
FIR_CS0
FCK
+5L
1
4.7K
FIR_CLK
D23
D22
D21
D20
D19
D18
D17
D16
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
CLR2
1
4
RP9E
RP12G
10K
1
A15 1
RP9A
J18
+5L
10K
2
+5L
A14
A13
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
27
26
2
23
21
24
25
3
4
5
6
7
8
9
10
A14
A13
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
4.7K
C127
.1uF
2
RP9B
1
A15 1
1
+5L
1
FIR_START
BR*/WT*
BG*/BS*
120
119
118
115
114
113
109
108
106
105
104
102
99
97
96
94
93
92
88
87
86
85
82
81
+5L
+5L
+5L
+5L
FIR_SEL
D23
D22
D21
D20
D19
D18
D17
D16
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
47K
1
S
6
10
CLR1
CLK2A
CLK2B
2QA
2QB
2QC
2QD
D7
D6
D5
D4
D3
D2
D1
D0
+5L
10K
J17
2
RP9C
10K
1
A15 1
4
J16
2
U28
U29
27C256
19
18
17
16
15
13
12
11
.1uF
3
A14
A13
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
D23
D22
D21
D20
D19
D18
D17
D16
27
26
2
23
21
24
25
3
4
5
6
7
8
9
10
A14
A13
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
27C256
D7
D6
D5
D4
D3
D2
D1
D0
19
18
17
16
15
13
12
11
U27
27C256
1
37
36
PC3/SC0
PC4/SC1
PC5/SC2
PC6/SCK
PC7/SRD
PC8/STD
CKK1A
CLK1B
A14
A13
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
D15
D14
D13
D12
D11
D10
D9
D8
27
26
2
23
21
24
25
3
4
5
6
7
8
9
10
A14
A13
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
22
43
44
1
31
40
37
32
42
39
1QA
1QB
1QC
1QD
13
11
10
9
1
SAMP_RATE_SEL
PC0/RXD
PC1/TXD
PC2/SCLK
4MHZ
8
42 FSYNC
40
41
FIR_CS0
IO_CS
/wr
FSTRT
CODEC_CLK
1
35
27
28
29
19
18
17
16
15
14
13
12
I/O1
I/O2
I/O3
I/O4
I/O5
I/O6
I/O7
I/O8
VPP
RXD
TXD
STROBE
A10
A9
A8
A7
I1/CLK
I2
I3
I4
I5
I6
I7
I8
I9
I10/OE*
CE
PIO1
PIO0
C0
C1
N/C
N/C
22pF
U39
1
2
3
4
5
6
7
8
9
11
FSYNC
/RESET
SAMP_RATE_SEL
SAMP_MODE
OE
SCLK
SDTX
SDRX
CODEC_CLK
A15
A14
A13
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
3
5
6
7
FCK
20
LOUT1L
LOUT1R
LOUT1C
4
5
80
79
77
76
75
71
70
68
67
65
61
60
58
57
54
53
.1uF
U40
/ds
x/y
22
EXTAL
XTAL
C131
1000PF
IN[0..17]
A15
A14
A13
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
CTRL1
CTRL0
10
127
126
MODA/IRQA*
MODB/IRQB*
/ps
/ds
x/y
1
27.0MHz
10
11
123
121
52
49
48
CE
69
72
78
83
84
89
95
98
103
107
110
116
117
122
125
132
FSYNC
R105
681K
CTRL3
CTRL2
VPP
FSYNC
TSIN
TSOUT
2
9
39
34
26
LOUT0L
LOUT0R
14
31
29
30
D/C
GNDA
GNDA
HEADPHONES
2
1
J15
MOUT
MOUTR
20
SEND_OUT
CALLER_OUT
Y1
PS*
DS*
X/Y*
/rd
/wr
OE
CLKIN
CLKOUT
22
25
32
33
6
7
RESET*
+5L
20
MINR
GND
GND
GND
27
28
1
J14
124
MINL
1
MONITOR
2
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
VREF
+VL
+VL
+VL
CIN2
COUT2
/RESET
C130
22pF
47
46
22
15
3
47K
LINR
12 /RESET
13
3
4
7
17
18
21
26
30
38
41
44
50
51
59
62
66
RP1B
1
17
J13
CIN1
COUT1
C150
22pF
.1uF
1
2
16
2
MIC IN
LINL
CMOUT
RD*
WR*
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
19
RP1A
22pF
C160
U30
DSP56001FE27
5
21
3
8
38
23
24
+VA
+VA
CALLER_IN
DSP CLOCK
/RESET
PDN
20.48MHz
C149
12
C159
18
C162
22pF
+5L
U19
AD1849
.22uF
D
Y2
74HCU04
S
C102
1
74HCU04
13
CODEC_COMM
47K
U41A
2
10
74HCU04
U41F
C124
.1uF
+VL
SEND_IN
74HCU04
3
C103
1uF
+
U41B
4
+5L
10.0M
U41E
11
VPP
S
C107
U41C
6
74HCU04
5
D7
D6
D5
D4
D3
D2
D1
D0
19
18
17
16
15
13
12
11
D7
D6
D5
D4
D3
D2
D1
D0
B
CE
S
D
R108
U41D
8
74HCU04
9
SAMP_RATE_SEL
7
.1uF
2
C87
.1uF
.1uF
RP12F
10K
RP12E
10K
C99
.1uF
OE
10uF
C93
C161
+5L
20
C94
C109
.1uF
1
3
VO
GND
VI
R100
4.7
1
1
C
SAMPLE CLOCK
OSCILLATOR
+5L
+5V
U15
LM7805
/ps
D[0..23]
CTRL[0..3]
A[0..8]
PROGRAM MEMORY
+5L
C19
C1+
C1C2+
C2-
V-
C34
10uF
A
14
COMM0
TX
COMM1
COMM2
COMM3
DSR
CTS
DCD
COMM4
RX
13
COMM5
DTR
8
7
T1OUT
T1IN
T2OUT
T2IN
R1IN
R1OUT
R2IN
R2OUT
1
3
4
5
11
C17
10uF
RP12H
10K
C18
10uF
RP12I
10K
WC
9
V+
GENTNER COMMUNICATIONS CORP
1825 RESEARCH WAY
SALT LAKE CITY, UTAH 84119
TXD
THIS DOCUMENT CONTAINS
INFORMATION PROPRIETARY
TO GENTNER COMMUNICATIONS CORPORATION AND
MAY NOT BE COPIED IN
WHOLE OR IN PART WITHOUT THE AUTHORIZATION
OF GENTNER COMMUNICATIONS CORPORATION.
10
12
CONTROL NO.
10
6
+
U3
2
+
C16
10uF
+
+
COMM[0..5]
1
.1uF
+5L
COMM[0..5]
1
+5L
RXD
9
DIMENSIONS IN INCHES
NOT TO SCALE
MAX232
A
GT724 DIGITAL SIGNAL PROCESSING
Size
Orcad C
Scale
FCSM No.
DWG No.
720-114-001
Rev
1.2
Sheet
2 of 7
1
2
3
4
5
6
1
2
3
U5-7
4 WIRE
L6
RECV_IN_+
U5-4
3
1
U5A
SSM2017
C65
.1uF
C64
.1uF
U11B
5
RECV_IN_TAP
C21
6
5
12uH
R11
20.0K
14
L4
2
C20
CLIP
P1
R51
11
9
C55
6
GAIN
R48
1.58K
10uF
C80
470PF
R90
R89
1.50K
10.0K
R86
+5L
10.0K
+
7
LF347
R57
1.00K
10.0K
10
-
5
R87
U10B
SW06
U12B
6
D
R62
9
10.0K
10
U12C
+
C90
R97
8
RECV_TO_CODEC
10.0K
LF347
C89
100pF
R64
1.00K
-12.78
10uF
7
8
220pF
P2
R50
4.32K
0
RECV_TELCO
2
R49
20.0K
20.0K
CUSTOM
C54
3
LF347
12uH
1000PF
R85
6.65K
1
U12-11
C71
.1uF
470PF
220pF
U11A
-
3
-15V
C79
15
16
1
TELCO
+
C22
1000PF
C5
470PF
7
C77
10uF
C6
470PF
U10A
SW06
LF347
13
L5
4_WIRE
2_WIRE
RECV_IN_POT
8
2
+15V
C69
.1uF
4_WIRE_A
6
R12
4.75K
U12-4
2/4 WIRE SWITCHING
RECEIVE INPUT LEVEL
-
R13
20.0K
6
-15V
U10-5
U10-12
C43
.1uF
+
C23 10uF
1000PF
RECV_IN_SHIELD
2_WIRE_A
CLIP
C78
100pF
R52
CODEC_COMM
U11-4
31.6K
C68
R55
PLAYBACK_IN
-
10
10uF
+
-15V
C66
.1uF
U11C
9
10.0K
+15V
C
C102
.22uF
U11-11
C67
.1uF
8
TAPE
LF347
R1
10k
*
R54
1.00K
U11D
12
+
C
-10
5
+15V
12uH
D
-15
4
-15V
C35
.1uF
C24
C7
470PF
RECV_IN_-
-10
+15V
13
-
R56
R88
14
LF347
10.0K
R17
10.0K
20.0K
C70
470PF
R61
10.0K
U12D
0
R58
FONEADD_OUT
13
-
14
1.00K
C56
220pF
R53
6.65K
10.0K
R60
12
+
R59
LF347
2.74K
R65
1.00K
DO NOT STUFF C3 AND C4
P_ADD
(NOT USED)
FONEADD_IN
TRAN_OUT_POT
R31
4
1
10.0K
3
LF347
SSM2142
3
8
U16-12
+
-
C96
A
470PF
2
C98
.1uF
0
-15V
R104
10.0K
10.0K
10
C101
.1uF
11
7
6
8
U17B
4700pF
7
13.3K
U17-5
U16B
SW06
R102
10.0K
5
6
7
C44
1800pF
10.0K
R3
U1D
U1B
LF347
11.0K
9
C46
R21
R35
604
11.0K
TRAN_FROM_CODEC
-12.78
10uF
C47
2200pf
R22
40.2K
4.99K
C95
.1uF
9
-
+15V
R101
C97
R103
U17-12
C100
.1uF
+
604
2
+5L
14
+
R6
6
10.0K
R32
13
R34
8.66K
2.74K
12
R19
WC
1.00K
U1-4
R2
2.55K
CLIP
10.0K
C37
R16
LF347
5
+15V
C36
.1uF
P3
CUSTOM
GAIN
0
4700pF
NE5532
U17A
3
1
3
-15V
13
R15
20.0K
C88
R47
U16-5
+15V
470PF
R20
10
R18
1800pF
1
U6-5
LF347
C26
15
16
TRAN_SAMPLE_OUT
TRAN_TELCO
U16A
SW06
14
R14
-10
U1C
TRAN_OUT_TAP
2
5.11K
C25
-15
1800pF
U1A
U4
1
2
TRAN_OUT_-
C45
-
-10
R7
10.0K
C41
.1uF
7
8
TRAN_OUT_+
10.0K
C4
1000pF 10uF
-
C42
.1uF
12uH
C3
470pF
-15V
B
R63
+
+15V
+
U4-6
C12
-
0
L3
+
B
470PF
CLIP
R33
P4
10.0K
-15V
C38
.1uF
GENTNER COMMUNICATIONS CORP
1825 RESEARCH WAY
SALT LAKE CITY, UTAH 84119
THIS DOCUMENT CONTAINS
INFORMATION PROPRIETARY
TO GENTNER COMMUNICATIONS CORPORATION AND
MAY NOT BE COPIED IN
WHOLE OR IN PART WITHOUT THE AUTHORIZATION
OF GENTNER COMMUNICATIONS CORPORATION.
DIMENSIONS IN INCHES
NOT TO SCALE
TRAN_RECORD_OUT
CONTROL NO.
U1-11
A
GT724 TELCO AND 4 WIRE I/O
Size
Orcad C
Scale
FCSM No.
DWG No.
720-114-001
Rev
1.2
Sheet
3 of 7
1
2
3
4
5
6
1
2
3
4
5
6
RX_TO_GT
RECV_OUT LEVEL
+
RECV_OUT_TAP
2
U13B
R94
7
9
1.33K
LF347
10
R92
R74
1.00K
10.0K
8
+
C48
470PF
R24
4.75K
+4
D
RECV_OUT_-
SSM2142
+15V
C27
U13C
-
U6 PIN 6
.1uF
LF347
+4
RECV_SAMPLE_OUT
BUFFER
R91
8.66K
R28
10
1.00K
+15V
C39
9
U2C
U2 PIN 4
C40
R23
1.00K
RECV_OUT_BRIDGE_2
0
RECV_OUT_BRIDGE_1
0
R36
.1uF
-15V
8
LF347
1.00K
U2 PIN 11
BUFFER
.1uF
U2B
R30
5
1.00K
6
C
-
6
C73
1800pF
R98
40.2K
C92
2200pF
5
+
10uF
10.0K
1800pF
RECV_OUT_+
1
2
10.0K
-
R93
11.0K
7
8
3
R25
+
R95
11.0K
-
604
+
C82
R96
RECV_FROM_CODEC
U6
4
LF347
R72
U5 PIN 5
.1uF
1
-
C91
C49
U2A
3
1800pF
D
-15V
STEP UP
RECV_OUT_POT
C81
7
LF347
R4
1.00K
C
R26
STEP DOWN SUMMER
C28
1.00K
470PF
R5
3.16K
R27
4_WIRE_A
13
10.0K
-
12
2_WIRE_A
U2D
+
R109
R9
14
RECORD_OUT
1.00K
LF347
-10
R29
1.00K
10.0K
R110
P_ADD
10.0K
J30
TAPE
R111
R8
10.0K
2.74K
TRAN_RECORD_IN
0
C163
470PF
R114
10.0K
SUMMER
B
U12A
TRAN_IN LEVEL
C75
470PF
-
1
TRAN_IN_POT
+
R113
2
10.0K
3
U9A
SSM2017
LF347
R71
R115
1.00K
STEP UP
1.50K
10.0K
10uF
C84
100pF
+
13
12
R68
10.0K
1
LF347
3
R37
12.4K
470PF
C74
U13 PIN 4
.1uF
C76
R69
C10
+15V
.1uF
R70
10.0K
C15
470PF
L8
C31
1000PF
10uF
TRAN_IN_-
12uH
C14
470PF
-15V
U9 PIN 4
L7
C59
.1uF
C29
1000PF
TRAN_IN_SHIELD
12uH
C13
470PF
C8
L1
12uH
10uF
C9
1000pF
TRAN_IN_BRIDGE_2
470pF
470pF
0
GENTNER COMMUNICATIONS CORP
1825 RESEARCH WAY
SALT LAKE CITY, UTAH 84119
THIS DOCUMENT CONTAINS
INFORMATION PROPRIETARY
TO GENTNER COMMUNICATIONS CORPORATION AND
MAY NOT BE COPIED IN
WHOLE OR IN PART WITHOUT THE AUTHORIZATION
OF GENTNER COMMUNICATIONS CORPORATION.
C1
GT724 ROOM I/O
Size
Orcad C
Scale
FCSM No.
DWG No.
720-114-001
Rev
1.2
Sheet
4 of 7
2
3
0
TRAN_IN_BRIDGE_1
C2
DIMENSIONS IN INCHES
NOT TO SCALE
1
+4
L2
C11
1000pF
10uF
A
C50
.1uF
12uH
10.0K
U13 PIN 11
TRAN_IN_+
12uH
U9 PIN 7
R66
3.32K
-15V
C30
7.50K
R67
C72
C32
1000PF
10uF
R38
TRAN_IN_TAP
2
10.0K
LF347
R73
1.00K
+15V
8
2
5
TRAN_TO_CODEC
U13D
14
-
R75
+
C83
7.50K
R40
12.4K
3
1
B
L9
R39
6
10.0K
U13A
-12.78
R112
C33
TX_FROM_GT
4
5
6
A
1
2
3
4
5
6
D
D
U8A
+15V
14
U14A
2
C57
-
3
RECV_SAMPLE_IN
10uF
+5L
R44
1
+
R46
+
R78
39.2K
C52
3.3uF
15
100K
1
2
3
221K
LF347
R76
100K
CEXT
REXT/CEXT
A
B
CLR
Q
Q
13
RECV_PEAK_OUT
4
74HC123
+5L
+5L
U8-16
C63
.1uF
R79
37.4K
U8B
6
+5L
U14B
+
R84
7
-
6
+
5
R45
C62
1uF
7
100K
9
10
11
221K
LF347
CEXT
REXT/CEXT
A
B
CLR
Q
Q
5
RECV_PRES_OUT
12
74HC123
R99
1.02K
C
C
+15V
-15V
U14-4
U14-11
C85
.1uF
C86
.1uF
U7A
+15V
14
U14C
9
C58
-
10
TRAN_SAMPLE_IN
10uF
R77
100K
+5L
R41
8
R43
+
R81
34.8K
15
100K
1
2
3
221K
+
CEXT
C51
3.3uF
LF347
REXT/CEXT
A
B
CLR
Q
Q
13
TRAN_PEAK_OUT
4
74HC123
+5L
+5L
U7-16
C61
.1uF
R80
45.3K
U7B
6
B
R83
14
-
R82
U14D
+
13
221K
R42
100K
+
12
+5L
C60
1uF
7
9
10
11
CEXT
B
REXT/CEXT
A
B
CLR
Q
Q
5
TRAN_PRES_OUT
12
74HC123
LF347
412
WC
CONTROL NO.
GENTNER COMMUNICATIONS CORP
1825 RESEARCH WAY
SALT LAKE CITY, UTAH 84119
THIS DOCUMENT CONTAINS
INFORMATION PROPRIETARY
TO GENTNER COMMUNICATIONS CORPORATION AND
MAY NOT BE COPIED IN
WHOLE OR IN PART WITHOUT THE AUTHORIZATION
OF GENTNER COMMUNICATIONS CORPORATION.
A
DIMENSIONS IN INCHES
NOT TO SCALE
A
GT724 AUDIO OUTPUT LEVEL DETECTORS
Size
Orcad C
Scale
FCSM No.
DWG No.
720-114-001
Rev
1.2
Sheet
5 of 7
1
2
3
4
5
6
1
2
3
4
5
6
FP_CTRL[0..16]
FP_CTRL[0..16]
LEVEL_LED[0..11]
LEVEL_LED[0..11]
+5L
D[0..23]
RP7A
1
270
RP7B
C120
IO_SEL
3
.1uF
G1
G2
FP_CTRL8
D7
D6
D5
D4
D3
D2
D1
D0
4_WIRE_SWITCH
12
13
14
15
16
17
18
19
270
RP7C
5
270
RP6A
1
270
RP6B
3
270
RP6C
1
11
PHONE_ADD_IN
7
Q7
Q6
Q5
Q4
Q3
Q2
Q1
Q0
OC
2_WIRE_SWITCH
9
8
7
6
5
4
3
2
LE
9
8
7
6
5
4
3
2
3
4
5
6
7
8
9
D23
D22
D21
D20
D19
D18
D17
D16
5
FP_CTRL9
1
19
A1
A2
A3
A4
A5
A6
A7
A8
2
RP2H
10K
U26
74HC541
Y1
Y2
Y3
Y4
Y5
Y6
Y7
Y8
U24
74AC573
1
1
1
1
1
RP2A
10K
IN[0..17]
18
17
16
15
14
13
12
11
1
1
C122
.1uF
IN0
IN1
IN2
IN3
IN4
IN5
IN6
IN7
270
RP7D
+5L
1
+5L
D
270
RP6D
7
2
SEND_IN_GN
LEVEL_LED0
4
SEND_IN_RD
LEVEL_LED1
8
SEND_OUT_GN
LEVEL_LED2
6
SEND_OUT_RD
LEVEL_LED3
2
CALLER_IN_GN
LEVEL_LED4
4
CALLER_IN_RD
LEVEL_LED5
6
CALLER_OUT_GN
LEVEL_LED6
8
CALLER_OUT_RD
LEVEL_LED7
2
AEC_GN
LEVEL_LED8
4
AEC_RD
LEVEL_LED9
6
AES_GN
LEVEL_LED10
8
AES_RD
LEVEL_LED11
D
270
PRIVACY_SWITCH
FP_CTRL10
+5L
RP5A
1
C119
270
.1uF
RP5B
3
PHONE_ADD_SWITCH
FP_CTRL11
270
U23
74AC573
D15
D14
D13
D12
D11
D10
D9
D8
FP_CTRL12
D7
D6
D5
D4
D3
D2
D1
D0
12
13
14
15
16
17
18
19
C
270
RP5D
7
270
2_WIRE
4_WIRE
1
11
FP_CTRL13
VOLUME_DOWN
5
Q7
Q6
Q5
Q4
Q3
Q2
Q1
Q0
LE
VOLUME_UP
9
8
7
6
5
4
3
2
OC
C
RP5C
C116
.1uF
LINE_STATUS
9
+5L
+5L
U20A
1
18
1
RP3A
270
2
2_WIRE_CONN
FP_CTRL0
2
2_WIRE_CONN_REMOTE
FP_CTRL1
270
4
4_WIRE_CONN
FP_CTRL2
270
4
4_WIRE_CONN_REMOTE
FP_CTRL3
270
6
PRIVACY
FP_CTRL4
270
6
PRIVACY_REMOTE
FP_CTRL5
270
8
PHONE_ADD
FP_CTRL6
270
8
PHONE_ADD_REMOTE
FP_CTRL7
AUX_CTRL
FP_CTRL16
0
LINE_STATUS
U20B
UDN2981A
17
0
2
RP4A 270
1
+5L
16
RP3B
UDN2981A
3
0
3
C118
.1uF
RP4B
U20D
U20C
UDN2981A
15
3
0
4
1
+5L
LE
RP12B
10K
FP_CTRL15
0
7
12
+5L
1
13
5
RP3D
UDN2981A
7
RP4D
B
8
11
7
U20H
UDN2981A
18
U21A
ULN2803A
17
TELCO_RELAY
U21B
ULN2803A
0
TRANSMIT_GREEN
16
0
3
IN11
6
U20G
UDN2981A
2
IN10
RP4C
U20F
0
Q7
Q6
Q5
Q4
Q3
Q2
Q1
Q0
3
AES_SWITCH
11
IN9
5
0
D7
D6
D5
D4
D3
D2
D1
D0
0
FP_CTRL14
2
AEC_SWITCH
RP3C
UDN2981A
U20E
UDN2981A
12
13
14
15
16
17
18
19
OC
IN8
9
8
7
6
5
4
3
2
14
1
1
D7
D6
D5
D4
D3
D2
D1
D0
RP12A
10K
B
5
U22
74AC573
10
+5L
TRANSMIT_RED
4
PHONE_ADD_ON
U21C
ULN2803A
15
PHONE_ADD_OFF
IN12
RECEIVE_GREEN
U21E
ULN2803A
5
14
0
+5L
0
U21D
ULN2803A
+5L
7
13
U21F
12
U21G
0
1
1
+5L
6
C117
.1uF
RECEIVE_RED
0
IN13
A
4
IN14
RP12D
10K
5
RP12C
10K
8
8
7
IN15
6
5
IN17
S1A
S1B
S1C
S1D
1
2
11
U21H
ULN2803A
OPTION SWITCH
OPTION SWITCH
3
WC
CONTROL NO.
GENTNER COMMUNICATIONS CORP
1825 RESEARCH WAY
SALT LAKE CITY, UTAH 84119
THIS DOCUMENT CONTAINS
INFORMATION PROPRIETARY
TO GENTNER COMMUNICATIONS CORPORATION AND
MAY NOT BE COPIED IN
WHOLE OR IN PART WITHOUT THE AUTHORIZATION
OF GENTNER COMMUNICATIONS CORPORATION.
4
DIMENSIONS IN INCHES
NOT TO SCALE
A
GT724 CONTROL I/O
Size
Orcad C
Scale
FCSM No.
DWG No.
720-114-001
Rev
1.2
Sheet
6 of 7
1
2
3
4
5
6
1
2
C148
3
C147
.1uF
C146
.1uF
+5L
C158
.1uF
C157
.1uF
C156
.1uF
C143
+5L
C137
.1uF
C155
.1uF
C142
.1uF
.1uF
+5L
C138
.1uF
6
C144
.1uF
+5L
C139
.1uF
5
C145
.1uF
+5L
C140
.1uF
4
.1uF
+5L
C136
.1uF
+5L
C153
.1uF
C135
C154
.1uF
.1uF
C134
.1uF
C152
.1uF
SEI
D
D
U38
18
19
20
21
24
25
26
27
D23
D22
D21
D20
D19
D18
D17
D16
5
8
6
SDO
SSO
START
16
17
/wr
/rd
CLK
SEI
SDI
SSI
7
FSTRT
U37
D7
D6
D5
D4
D3
D2
D1
D0
A3
A2
A1
A0
/WR
/RD
9
2
FCK
D23
D22
D21
D20
D19
D18
D17
D16
5
8
6
4
3
13 A3
12 A2
11 A1
10 A0
18
19
20
21
24
25
26
27
FSTRT
/wr
/rd
7
16
17
9
/CS
DSP56200
D7
D6
D5
D4
D3
D2
D1
D0
SEI
SDI
SSI
START
/WR
/RD
U36
CLK
SDO
SSO
A3
A2
A1
A0
2
FCK
D23
D22
D21
D20
D19
D18
D17
D16
5
8
6
4
3
13 A3
12 A2
11 A1
10 A0
18
19
20
21
24
25
26
27
FSTRT
/wr
/rd
7
16
17
9
/CS
DSP56200
U35
D7
D6
D5
D4
D3
D2
D1
D0
CLK
SEI
SDI
SSI
SDO
SSO
START
A3
A2
A1
A0
/WR
/RD
2
18
19
20
21
24
25
26
27
D23
D22
D21
D20
D19
D18
D17
D16
FCK
D7
D6
D5
D4
D3
D2
D1
D0
5
8
6
4
3
13 A3
12 A2
11 A1
10 A0
FSTRT
SEI
SDI
SSI
7
START
16
17
/wr
/rd
/WR
/RD
9
/CS
U34
2
CLK
FCK
18
19
20
21
24
25
26
27
D23
D22
D21
D20
D19
D18
D17
D16
5
8
6
4
3
SDO
SSO
13 A3
12 A2
11 A1
10 A0
A3
A2
A1
A0
FSTRT
9
/CS
DSP56200
7
16
17
/wr
/rd
DSP56200
D7
D6
D5
D4
D3
D2
D1
D0
SEI
SDI
SSI
START
/WR
/RD
U33
CLK
SDO
SSO
A3
A2
A1
A0
2
FCK
D23
D22
D21
D20
D19
D18
D17
D16
5
8
6
4
3
13 A3
12 A2
11 A1
10 A0
18
19
20
21
24
25
26
27
FSTRT
/wr
/rd
7
16
17
9
/CS
DSP56200
U32
D7
D6
D5
D4
D3
D2
D1
D0
2
CLK
SEI
SDI
SSI
13 A3
12 A2
11 A1
10 A0
A3
A2
A1
A0
/WR
/RD
18
19
20
21
24
25
26
27
5
8
6
4
3
SDO
SSO
START
FCK
D23
D22
D21
D20
D19
D18
D17
D16
FSTRT
/wr
/rd
7
16
17
9
/CS
DSP56200
D7
D6
D5
D4
D3
D2
D1
D0
CLK
SEI
SDI
SSI
SDO
SSO
START
A3
A2
A1
A0
/WR
/RD
2
FCK
4
3
SDO
SSO
13 A3
12 A2
11 A1
10 A0
/CS
DSP56200
C141
+5L
C
C151
C133
.1uF
+5L
C121
C
.1uF
.1uF
.1uF
U31
U25
1
2
3
A4
A5
A6
+5L
A
B
C
6
4
5
Y0
Y1
Y2
Y3
Y4
Y5
Y6
Y7
G1
G2A
G2B
18
19
20
21
24
25
26
27
D23
D22
D21
D20
D19
D18
D17
D16
15
14
13
12
11
10
9
7
5
8
6
74HC138
FSTRT
/wr
/rd
7
16
17
9
D7
D6
D5
D4
D3
D2
D1
D0
CLK
SEI
SDI
SSI
SDO
SSO
START
A3
A2
A1
A0
/WR
/RD
2
FCK
4
3
13
12
11
10
A3
A2
A1
A0
/CS
DSP56200
FIR_SEL
B
A[0..8]
A[0..8]
B
D[16..23]
JP15
JP14
JP13
JP12
JP11
JP10
JP9
JP8
JP7
JP6
JP5
JP4
+5L
FIR_CLK
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
JP16
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
A8
A7
A6
A5
A4
A3
A2
A1
A0
SDO
SSO
SEI
FSTRT
JP3
JP2
J20
1
CTRL3
CTRL2
CTRL1
CTRL0
D23
D22
D21
D20
D19
D18
D17
D16
/rd
/wr
/ds
x/y
FCK
2
CTRL[0..3]
CTRL[0..3]
JP1
FIR_START
WC
A
C125
22pF
R106
47.5
C126
22pF
CONTROL NO.
FIR EXPANSION
CONNECTOR
GENTNER COMMUNICATIONS CORP
1825 RESEARCH WAY
SALT LAKE CITY, UTAH 84119
THIS DOCUMENT CONTAINS
INFORMATION PROPRIETARY
TO GENTNER COMMUNICATIONS CORPORATION AND
MAY NOT BE COPIED IN
WHOLE OR IN PART WITHOUT THE AUTHORIZATION
OF GENTNER COMMUNICATIONS CORPORATION.
R107
47.5
CLOCK TERMINATIONS
DIMENSIONS IN INCHES
NOT TO SCALE
A
GT724 FIR FILTERS AND EXPANSION BUS
Size
Orcad C
Scale
FCSM No.
DWG No.
720-114-001
Rev
1.2
Sheet
7 of 7
1
2
3
4
5
6