GAI-Tronics 305-002 User Manual

Pub. 42004-323C

GAI-TRONICS® CORPORATION

A HUBBELL COMPANY

Model 305-002

600-Ohm 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.
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 GAI-Tronics Model 305-002 Line Balance Assembly is designed to properly load both the page and
party line circuits of a GAI-Tronics 600-ohm Page/Party
assembly must be installed in each system. The line balance assembly may be used in single or multi (up
to five) party line systems.

®

communication system. One line balance

Installation

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 26,400 feet (5 miles or 8 km) from the most distant station, when used with

GAI-Tronics’ standard cable. For larger systems or when non-standard cable is to be used, please
contact a GAI-Tronics representative for further information.

Mounting can be accomplished by either suspending the assembly by a 1-inch conduit nipple (not
supplied) from the bottom of an indoor wall station or by using the mounting ears located on the box.
Connect one twisted pair for the page circuit and a similar pair for each party line between the terminal
blocks of the line balance assembly and the associated indoor wall station.

Adjustment

To set the control for proper page circuit loading and to minimize the receiver sidetone, complete the
steps listed below. Sidetone is the amount of signal returned from the microphone to the receiver element
of the handset, i.e., how loudly the user hears his or her own voice. This adjustment needs to be made
during the initial installation of the system. However, if more than ten handset stations or speaker
amplifiers are added or deleted in the system at any time, readjust the page circuit loading.

GAI-Tronics Corporation 400 E. Wyomissing Ave. Mohnton, PA 19540 USA

610-777-1374  800-492-1212  Fax: [phone]

V

ISIT WWW.GAI-TRONICS.COM FOR PRODUCT LITERATURE AND MANUALS

Pub. 42004-323C

Model 305-002 600-Ohm Line Balance Assembly Page 2 of 2

1. Remove the line balance assembly cover to expose the line balance control.

2. Lift the handset from the adjacent station and press the P

AGE button.

3. Blow steadily into the handset microphone and adjust the control to minimize receiver sidetone.

4. After final adjustment, replace the cover and secure it with four mounting screws.

Each amplifier has a paging speaker volume control, accessible from the front panel with a screwdriver.
It is concealed behind the metal nameplate. To access the control, loosen (do not remove) the two
nameplate screws and pivot the nameplate around the left screw. This control is preset at the factory for a
moderate 4-watt output to the connected speaker.

For more detailed system installation information, please refer to GAI-Tronics Pub. 42004-324.

Figure 1. 305-002 Terminal Connections

Specification s

Terminations ............................ Barrier-type terminal blocks for field wiring to page and party line circuits

Mounting ....................................Mounting lugs or support by 1-inch NPT pipe nipple from handset station

Enclosure ................................... Cast aluminum two-gang outlet box with cast, dust-tight aluminum cover

Control ................................................................ Rheostat adjustment control provided for page line 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)

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