Clear-Com PS-704 - Manual (Page 14)

P S - 7 0 4 F O U R - C H A N N E L P O W E R S U P P L Y 1 - 8
Caution: Pin #1 and the shell of the XLR plug on the interconnect
cables should NOT be connected together.
CHECK INTERCOM CABLE RESISTANCE
For minimal crosstalk, the ground resistance of the intercom cables should be
as low as possible, preferably less than 2
Ω. Disconnect an intercom line from
the main station or power supply. At the point in the intercom line furthest
from the unit, connect a clip lead jumper between pins #1 and #2. Back at the
“powered” end, use an Ohmmeter to measure the resistance between pins #1
and #2. A value of less than 4
Ω is ideal.
FINAL TESTS
After you turn the power on:
1. Check for proper voltage on pin #2 of any intercom line or jack in a
channel. It should read 26 to 30 volts.
2. Test for proper operation of call signaling. Activate the call signal on any
belt pack or station. The call lights on all other stations on that channel
should illuminate and then go out when the call button is released.
3. Adjust the sidetone null on all stations. (Refer to the manual for each
specific unit for instructions.)