GAI-Tronics 700 Series 24 V DC Page/Party Systems - Manual (Page 8)

Pub. 42004-140E
Installation of GAI-Tronics 700 Series 24 V DC Page/Party
®
Systems Page 8 of 13
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Adjustment of the Line Balance Assembly
To set the control for proper page circuit loading:
1. Remove the line balance assembly cover to expose the line balance control.
2. Lift the handset from the adjacent handset hook and press the push-to-page button. From the normal
speaking distance (approximately ½ inch), blow steadily into the handset microphone and adjust the
control to minimize receiver sidetone. This adjustment needs to be made only at the initial
installation of the system. However, if in the future more than 10 speaker amplifiers are added or
deleted, repeat adjustment of page circuit loading.
3. After final adjustment, replace and secure the cover with the four mounting screws to discourage
tampering by unauthorized personnel and prevent entry of contaminants.
Each amplifier has a paging speaker volume control. It is accessible from the front panel with a
screwdriver, but is concealed behind the metal GAI-Tronics nameplate. To reach it, simply loosen (do
not remove) the two nameplate screws and pivot the nameplate around the left screw. This control is
adjusted at the factory so that a moderate page level produces 4 watts of output power.
Each handset/speaker amplifier has three additional internal controls: receiver volume control,
transmission volume control, and receiver sidetone control. All controls are accessible using a
screwdriver through the holes in the chassis. A fourth hole allows similar access from the rear of the
paging speaker volume control. Controls are factory-adjusted for optimum results in most industrial
applications. Do not readjust these controls to solve system problems until other possible faults are
checked, such as a missing, defective or improperly connected line balance assembly.
There is very little drop in receiver (handset earpiece) volume level due to system cable losses. Generally
speaking, the only reason to reset the receiver volume control is to compensate for extremely high
ambient noise levels (up to 110 dB), or to meet particular personnel needs.
At stations with cable lengths of 3,000 feet (1 km) or more from the line balance assembly, receiver
sidetone rejection is noticeably affected by cable impedance. Use the receiver sidetone control to
compensate for this by rotating the control clockwise approximately 60 degrees for 3,000 feet (1 km) of
cable length.