GAI-Tronics Associated with 600-ohm systems Extended Range Page/Party System Manual - Manual (Page 5)

Pub. 42004-324A
Extended Range Page/Party
®
Systems Page: 5 of 10
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STEP 6 - Checkout and Adjustment
Verify all field-wiring connections (e.g., page line, party lines, mute, ac power and speaker) between
stations, and complete the line balance assembly installation before checkout begins. Ensure that all
handsets are on-hook.
1. Apply ac power, and check the station located next to the line balance assembly.
2. Press the PUSH - TO - PAGE switch on the handset and speak directly into the microphone. The broadcast
should be heard at all paging speakers in the system except those associated with the station under test.
If working properly, very little or none of your own voice (sidetone) is heard from the handset earpiece.
If the line balance assembly is not connected properly, there will be a high level of sidetone, perhaps
enough to cause feedback. Adjust the line balance assembly to optimize sidetone rejection on the page
line. If the system is complete when the first station is checked, adjust the line balance assembly as
noted below. Do not adjust station (amplifier) controls until the line balance assembly is adjusted.
3. Release the PUSH - TO - PAGE switch and check the party line(s) sidetone level by speaking into the
microphone of the handset. If working properly, very little or none of your own voice is heard from the
handset earpiece. This sidetone rejection will only occur if the line balance assembly is properly
connected because it contains a fixed resistor load for each party line. In addition, no party line
adjustments are provided. Check party line operation by conversing between two or more stations.
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 station located next to the line balance assembly and press the push-to-page
button.
3. From the normal speaking distance (approximately ½-inch), blow steadily into the handset microphone
and adjust the line balance control to minimize side tone in the handset receiver. 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.
4. 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 nameplate. To access it, simply loosen (but do not remove)
the two nameplate screws and pivot the nameplate around the left screw. This control is pre-set at the
factory to produce a moderate page level of approximately 4 watts of output power.
Each handset/speaker station amplifier has two additional internal controls: receiver volume control and
receiver sidetone control. Both controls are accessible from the rear using a small screwdriver through
holes provided on the chassis. A third hole allows similar access from the rear for the paging speaker
volume control. All controls are factory-adjusted for optimum performance 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, 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.
For stations with cable lengths of 26,400 feet (5 miles or 8 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.