Pub. 42004-261F
Model 7245-003
24 V DC Remote Subset Amplifier Enclosure
Confidentiality Notice
This manual is provided solely as an operational, installation, and maintenance guide and contains
sensitive business and technical information that is confidential and proprietary to GAI-Tronics.
GAI-Tronics retains all intellectual property and other rights in or to the information contained herein,
and such information may only be used in connection with the operation of your GAI-Tronics product or
system. This manual may not be disclosed in any form, in whole or in part, directly or indirectly, to any
third party.
General Information
The Model 7245-003 Indoor Remote Subset Amplifier Enclosure is an important component of the 700
Series Page/Party® system. It is constructed of fabricated steel, and is equipped with terminal strips for
connecting inter-station cable and a 24-pin connector to accommodate one of three types of GAI-Tronics
subsets. The GAI-Tronics Model 723-003 Amplifier plugs directly into this enclosure.
The Model 7245-003 Amplifier Enclosure must be mounted within 8 feet of the subset due to the subset
cable limitations. In addition, it must be mounted at an indoor location - the amplifier enclosure is not
designed for outdoor use.
Do not install this equipment in hazardous areas or areas other than those
indicated on the approval listing in the “Specifications” section of this manual. Such installation
may cause a safety hazard and consequent injury or property damage.
When installing an add-on station, consult the 24 V dc system layout diagrams at the end of this manual.
These figures, when used in conjunction with the station installation information and cable layout guide,
should provide all the information necessary to install additional Page/Party stations.
In 24-volt systems, plan on several branch lines from the dc source with no more than six stations per
branch. One branch could span up to 4,000 feet for a single station. The Maximum Cable Distance Table
lists the limits. Where two or more stations are listed, the assumption is that they are evenly spaced along
the cable.
GAI-Tronics Corporation 400 E. Wyomissing Ave. Mohnton, PA 19540 USA
610-777-1374  800-492-1212  Fax: 610-796-5954
Model 7245-003 24 V DC Remote Subset Amplifier Enclosure
Pub. 42004-261F
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Each amplifier contains two fuses on the PCBA in the 24 V dc input to protect and isolate the handset and
speaker amplifier circuitry in the event of a failure. Power line wiring to each amplifier or group of
amplifiers should have a fuse or circuit-breaker to protect against wiring failures.
If cable with No. 14 AWG power line conductors is used, a 15-amp fuse or circuit breaker should be
installed for each branch line at the point it connects to the battery. Fuse or circuit breaker rating is
determined by the size cable used in the branch. Consult the National Electrical Code (NFPA70) or
Canadian Standards Association (CSA 22.1) for the maximum allowable capacity of the wire used.
The GAI-Tronics 24 V dc series of Page/Party® system equipment is designed to operate from a 24 volt
dc rechargeable battery. A battery charger may be connected to the battery to maintain the charge.
Under NO condition should this equipment be operated from a battery
charger without the batteries connected.
Most chargers have an unloaded output of 35 to 45 volts that can quickly damage the equipment designed
for nominal 24 volts. To maintain a proper state of battery charge, the voltage across the batteries will be
somewhat greater than 24 volts, but should never exceed 28.8 V dc. Grounding the negative side of the
battery system at only one point is recommended and will ensure hum- and noise-free operation.
Enclosure Placement
All GAI-Tronics Page/Party® units are wired in parallel. Good system layout design minimizes the cable
required for each installation. GAI-Tronics multi-conductor cable, designed especially for this
application, is recommended. The number, size, and color-coding of conductors are listed in the
accompanying system connection diagrams.
System layout and power cable length are important considerations when installing Page/Party®
equipment. Consult the Maximum Cable Distance table for typical cable lengths. The cable distance
between stations as well as total cable distance must be considered. Cable distance is more strictly
regulated in 24 V dc systems because of the amount of resistance these cables encounter—the longer the
cable distance, the greater the resistance and IR losses (voltage drop) encountered.
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Model 7245-003 24 V DC Remote Subset Amplifier Enclosure
Maximum Cable Distance in Feet*
Number of
No. 14 AWG
Total / Between
No. 12 AWG
Total / Between
No. 10 AWG
Total / Between
No. 8 AWG
Total / Between
977 / 977
1,554 / 1,554
2,471 / 2,471
3,931 / 3,931
651 / 325
1,037 / 518
1,648 / 824
2,620 / 1,310
489 / 163
777 / 259
1,236 / 412
1,966 / 655
391 / 98
622 / 155
988 / 247
1,572 / 393
325 / 65
518 / 103
823 / 165
1,310 / 262
279 / 46
444 / 74
706 / 117
1,123 / 187
196 / 21
311 /34
494 / 55
786 / 87
*Based on the following assumptions:
 Continuous tone (alarm) signals driving each station’s speaker amp to a maximum of 12 watts.
NOTE: If the station is used for speech (audio) signals only, the distances stated above can be
multiplied by a factor of 2 because speech signals do not have the energy content that a
continuous tone has; therefore, they do not require as much average current and thus less cable IR
drop will result.
 GAI-Tronics-supplied cable is used.
 Wire resistance (ohms) is the nominal value for the applicable AWG at 1,000 feet of bare copper,
stranded wire @ 20º C (68º F). Wire resistance values used are as follows:
No. 14 AWG = ~2.525 ohms; No. 12 AWG = ~1.588 ohms; No. 10 AWG = ~0.999 ohm; No. 8 AWG = ~0.628 ohm
DC V at cable run’s feed point (Float charge of connected batteries) = ~26.6 V dc
DC V at the last unit in cable run = 21 V dc minimum
Station unit current draw (I) is the same regardless of the unit’s placement along the cable run for
ease of calculation. (1.1 amperes when unit is producing a 12-watt sine wave output.)
Distances reflect a 3% reduction for margin of error.
For conditions other than above, the following formula may be helpful in calculating the approximate
maximum distance for a SINGLE station.
For CONTINUOUS tone applications with minimum distortion:
For SPEECH operation only, multiply the above result by a factor of 2.
Example: What is the approximate maximum distance for a single dc station if the voltage feed is 27.5 V
dc and a No. 14 AWG wire is used @ 20º C?
 No. 14 AWG @ 20º C = ~0.002525 ohm per foot  2 for LOOP R
 VFEEDPOINT = 27.5 V dc
(27.5 V – 21 V) / ((2  0.002525 ohm per foot)  1.1 amps)
= 6.5 / 0.005555
= 1,170 feet (for CONTINUOUS TONE signal), or up to ~2,340 feet (factor of 2) for SPEECH signals
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Model 7245-003 24 V DC Remote Subset Amplifier Enclosure
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Refer to Figure 1 for a typical installation of desk-edge or desktop subsets stations in the knee-well of the
desk. Refer to Figure 2 for a typical installation of flush-mount subset stations. Place the enclosure in a
location that provides easy installation and removal of the connectorized subset cabling, the plug-in
amplifier, the speaker cabling, and the system cabling.
NOTE: The GAI-Tronics subsets designed for use with this enclosure contain 8-foot (244 cm)
connectorized cables. This enclosure must be mounted within reach of these cables.
Figure 1. Typical Desk-edge Installation
Figure 2. Typical Flush-mount Installation
The Model 7245-003 Indoor Enclosure is not supplied with openings for conduit or cable. Drill or punch
these openings using the supplied template before mounting the enclosure. The best location for the
conduit holes is along the top or bottom of the enclosure and near the rear surface. Avoid the top center
as it may interfere with the plug-in amplifier receptacle.
In extreme environments, extra precautions should be taken to improve system reliability. Whenever
possible, do not install conduit from the top. Side or bottom entry helps to prevent moisture from
dripping onto the terminals or printed circuit boards.
There are four 0.312-inch diameter mounting holes in the corners of the amplifier enclosure. See Figure 3
for dimensions. When mounting the enclosure, use caution to avoid damaging the terminal blocks inside.
Install the connector guard over the remote cable plug using the screws provided as shown in Figure 3 to
comply with NRTL requirements.
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Model 7245-003 24 V DC Remote Subset Amplifier Enclosure
Figure 3. Mounting Details
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Model 7245-003 24 V DC Remote Subset Amplifier Enclosure
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Attach the conduit to the enclosure. Feed the wiring through the conduit and bring it into the enclosure.
See Figure 4. Follow the wire colors carefully because the colors correspond to GAI-Tronics 60029 or
60038 Series multi-party cable. The wires must be spade-lugged and connected carefully and completely
to the terminal block. An improper termination may result in diminished station performance.
1. Set the speaker muting control to the desired location. Refer to the “Local Muting” and “Mutual
Muting” sections for details.
2. Plug the subset connector into the receptacle located at the bottom of the enclosure. Secure the
connector with the connector guard and screws provided. See Figure 3.
3. Insert the plug-in amplifier into the enclosure and secure the amplifier with four screws.
Local Muting
Figure 4 illustrates local speaker muting when stations are completely assembled and paging operation
occurs. Normally, when the station button is pressed, the paging speaker connected to that station is
silenced (muted) to prevent acoustic feedback to the handset microphone. However, while the handset is
in use for party line conversations, the paging speaker is “live” to enable paging calls from other stations.
To disable the mute feature, follow these instructions:
1. Locate the lugged violet wire attached to terminal point 7 (mute) on the terminal block within the
2. Transfer the lugged violet wire to terminal point 8 (Page L1).
After any muting changes are made, unpack the station amplifier and install.
Mutual Muting
In the event that feedback occurs within an area and repositioning of the system speakers does not help,
mutual muting may be used to correct this problem.
Perform the following steps to mutually mute adjacent amplifiers/handsets within a zone.
1. Ensure that the purple lugged wire is connected to terminal 7 of TB1.
2. Connect terminal TB1-7 of the handset station to TB1-7 of the station within the zone that is causing
feedback. This is done by using the spare system wire (orange conductor) from within the system
cable that runs between the stations.
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Model 7245-003 24 V DC Remote Subset Amplifier Enclosure
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Figure 4. Wiring Details
Regular inspection and a good preventive maintenance program will increase the reliability of your
GAI-Tronics station. The GAI-Tronics Field Service Department can formulate a service contract suited
to your facility’s specific need for preventive maintenance.
In addition, the following procedure can be used to keep Page/Party® systems operating effectively.
Before performing any of the following preventive maintenance steps, remove
all power from the station.
1. Remove the amplifier from the enclosure.
2. Visually check the interior of the enclosure for signs of contamination such as dust, condensation or
process liquid.
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Model 7245-003 24 V DC Remote Subset Amplifier Enclosure
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3. Using the No. 10440-003 Maintenance Cable, plug the amplifier into the connector in the enclosure.
Check, and if necessary, adjust the amplifier to maximize performance.
4. Reinstall the amplifier in the enclosure. Ensure that all gaskets and hardware are in place. Failure to
install the gaskets, which also act as spacers, can result in damage to the connectors on the amplifiers
and inside the enclosures and can cause system faults.
It may become necessary to re-terminate some or all of the enclosures in a system. If so, strip the wires
back to clean copper and connect only one wire to each connector to allow for easier future
The following table lists some hints to aid technicians in troubleshooting.
occurs only
during page.
1. If a speaker is close to the station, try using the muting feature in the amplifier
enclosure at the terminal blocks. Connect the violet wire at TB1-8 to TB1-7.
Refer to the wiring diagram.
2. Ensure that speakers attached to other stations located nearby are not pointed in
your direction. If changing the orientation of the other speakers has no effect,
mutual muting may be required. Mutual muting silences all the speakers within
proximity to the affected stations during a page from any one of the mutually
muted stations.
Connect the orange wire (spare) to the TB1-7 of all the stations to be mutually
muted. NOTE: If too many stations are selected, paging coverage can be
adversely affected.
3. Check line terminations at the line balance assembly. Line balance assembly
connections are critical.
Remote subset
is inoperable.
Verify that the connector of the remote subset is securely connected to the subset
receptacle of the enclosure.
Remove the amplifier from the enclosure. Re-install the amplifier ensuring the
enclosure connector and the amplifier connector are aligned properly.
One or more system cable pairs may be improperly terminated. Visually inspect the
system cable connections for accidental crossing of the cable pairs or grounds.
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Model 7245-003 24 V DC Remote Subset Amplifier Enclosure
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Construction/finish.................................................................. 16-gauge cold-rolled steel/gray polyurethane
Mounting .......................................... Wall or column, four 0.312-inch (7.92 mm) diameter mounting holes
Connections............................................................................... Internal screw-type barrier terminal blocks;
24-pin subset connector
Dimensions ................................................................ 8.1 H  8.1 W  5.1 D inches (206  206  129 mm)
Shipping weight .................................................................................................................... 5.5 lbs. (2.5 kg)
Temperature range ................................................................................. −22º F to 158º F (−30º C to +70º C
Relative humidity ....................................................................................... Non-condensing, 85% maximum
Indoor environmental rating ................................................................................ Meets requirement of IP20
NRTL certified for use in US and Canada ............................................... Class I, Div. 2, Groups A, B, C, D
CE Mark
Replacement Parts
Part Number
Harness Assembly
Hardware Kit for Harness Assembly
Maintenance Cable
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Model 7245-003 24 V DC Remote Subset Amplifier Enclosure
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GAI-Tronics warrants for a period of one (1) year from the date of shipment, that any
GAI-Tronics equipment supplied hereunder shall be free of defects in material and workmanship, shall
comply with the then-current product specifications and product literature, and if applicable, shall be fit
for the purpose specified in the agreed-upon quotation or proposal document. If (a) Seller’s goods prove
to be defective in workmanship and/or material under normal and proper usage, or unfit for the purpose
specified and agreed upon, and (b) Buyer’s claim is made within the warranty period set forth above,
Buyer may return such goods to GAI-Tronics’ nearest depot repair facility, freight prepaid, at which time
they will be repaired or replaced, at Seller’s option, without charge to Buyer. Repair or replacement shall
be Buyer’s sole and exclusive remedy. The warranty period on any repaired or replacement equipment
shall be the greater of the ninety (90) day repair warranty or one (1) year from the date the original
equipment was shipped. In no event shall GAI-Tronics warranty obligations with respect to equipment
exceed 100% of the total cost of the equipment supplied hereunder. Buyer may also be entitled to the
manufacturer’s warranty on any third-party goods supplied by GAI-Tronics hereunder. The applicability
of any such third-party warranty will be determined by GAI-Tronics.
Any services GAI-Tronics provides hereunder, whether directly or through subcontractors,
shall be performed in accordance with the standard of care with which such services are normally
provided in the industry. If the services fail to meet the applicable industry standard, GAI-Tronics will
re-perform such services at no cost to buyer to correct said deficiency to Company's satisfaction provided
any and all issues are identified prior to the demobilization of the Contractor’s personnel from the work
site. Re-performance of services shall be Buyer’s sole and exclusive remedy, and in no event shall GAITronics warranty obligations with respect to services exceed 100% of the total cost of the services
provided hereunder.
Warranty Periods.
Every claim by Buyer alleging a defect in the goods and/or services provided
hereunder shall be deemed waived unless such claim is made in writing within the applicable warranty
periods as set forth above. Provided, however, that if the defect complained of is latent and not
discoverable within the above warranty periods, every claim arising on account of such latent defect shall
be deemed waived unless it is made in writing within a reasonable time after such latent defect is or
should have been discovered by Buyer.
Limitations / Exclusions.
The warranties herein shall not apply to, and GAI-Tronics shall not be
responsible for, any damage to the goods or failure of the services supplied hereunder, to the extent
caused by Buyer’s neglect, failure to follow operational and maintenance procedures provided with the
equipment, or the use of technicians not specifically authorized by GAI-Tronics to maintain or service the
Return Policy
If the equipment requires service, contact your Regional Service Center for a return authorization number
(RA#). Equipment should be shipped prepaid to GAI-Tronics with a return authorization number and a
purchase order number. If the equipment is under warranty, repairs or a replacement will be made in
accordance with the warranty policy set forth above. Please include a written explanation of all defects to
assist our technicians in their troubleshooting efforts.
Call 800-492-1212 (inside the USA) or 610-777-1374 (outside the USA) for help identifying the
Regional Service Center closest to you.
(Rev. 10/06)
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