GAI-Tronics 305-001 User Manual
Pub. 42004-165E
GAI-TRONICS® CORPORATION
A HUBBELL COMPANY
Model 305-001 Line Balance Assembly
Confidential ity 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. GAITronics 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 GAI-Tronics Model 305-001 Line Balance Assembly has been designed to properly load both page
and party line circuits of a GAI-Tronics communication system. At least one line balance assembly must
be installed in each system. The Model 305-001 Line Balance Assembly can be used in single or multiple
(up to five) party line systems.
Installation
Location
There are three primary considerations in determining the location of the line balance assembly:
1. It should be near the electrical center of the system;
2. It should be adjacent to an indoor station in a relatively quiet area;
3. It should be no more than 5,280 feet (1600 m) from the most distant station, when used with standard
GAI-Tronics cable.
For larger systems or when non-standard cable is to be used, please contact a GAI-Tronics representative
for further information. The line balance assembly has one electrical adjustment that must be made while
using a station. See the “Line Balance Assembly Adjustment” section.
Mounting
Mounting can be accomplished by either suspending the line balance assembly by a one-inch conduit
nipple (not supplied) from the lower side of an indoor wall station, or by using the mounting ears located
on the box.
Wir in g
Use one twisted pair for the page circuit and one simila r pair for each par ty line to connec t the terminal
blocks of the line balance assembly and the associated indoor wall station.
GAI-Tronics Corporation 400 E. Wyomissing Ave. Mohnton, PA 19540 USA
610-777-1374 800-492-1212 Fax: 610-796-5954
V
ISIT WWW.GAI-TRONICS.COM FOR PRODUCT LITERATURE AND MANUALS
Pub. 42004-165E
Model 305-001 Line Balance Assembly Page 2 of 2
Figure 1. Line balance assembly terminal block connections
Line Balance Assembly Adjust ment
1. Remove the line balance assembly cover to expose the line balance control.
2. To set the control for proper page circuit loading, lift the handset from the adjacent handset station
and press the push-to-page button. From a normal speaking distance (approximately 1/2 inch), blow
steadily into the handset microphone and adjust the control to minimize receiver sidetone.
(Sidetone is the amount of signal transmitted from the microphone of a handset to the ear piece, i.e.,
how loudly the speaker hears their own voice.)
OTE: This adjustment needs to be made only at the initial installation of a system. However, if
N
more than 10 speaker amplifiers are added or deleted, repeat the adjustment of page circuit loading.
3. After final adjustment, replace the cover and secure with four mounting screws to discourage
tampering by unauthorized personnel and prevent entry of contaminants.
For more detailed system installation information, please refer to GAI-Tronics Pub. 42004-139 for 700
Series 120 V ac systems, or Pub. 42004-140 for 700 Series 24 V dc systems.
Specification s
Wiring ..................................................... The assembly contains a barrier-type terminal strip to which field
wiring connections are made to page and party line circuits.
Mounting ................................................. Mounting lugs or supported by a 1-inch conduit nipple connected
between the conduit hub and the handset station.
Enclosure ................................... Cast aluminum two-gang outlet box with cast, dust-tight aluminum cover
Control ......................................................................... Line balance control is provided for the page circuit
Finish .............................................................................................................................. Aluminum or epoxy
Dimensions ................................................... 5.30 H 4.60 W 2.25 D inches (134.6 116.8 57.2 mm)
Shipping weight ....................................................................................................................... 2 lbs. (0.9 kg)
Approvals
NRTL Listed for USA and Canada ......................................................... Class I, Div. 2, Groups A, B, C, D;
Class II, Div. 2, Groups F and G; Class III, Div. 2
CE Mark
f:\standard ioms - current release\42004 instr. man uals\42004-165e.doc
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