Ring Communications CB901EX - Manual (Page 24)

CB901EX Operations Manual March 2011
Plug in the rest of the NFE1625/PCB978 cards, one by one and connect the corresponding flat
cable to the back of the motherboard in the cardrack. Make a call between the stations in positions 00
and 01.
ADJUSTMENTS
Normally no adjustments are necessary, but it is advisable to check status of:
A. The -5V Level Measure on the motherboard, on the plug of the programming card (card
position 20) that the exact value of the -5V. 0V is on pin No. 3a/b and -5V is on pin
1a/b. Both on plug P1 (the lower plug). The correct voltage to measure is between 5,0
and 5,1V. If adjustment is necessary, turn potentiometer R19 on power card PCB1016.
B. Duplex Switching. It is necessary to check the audio control card NFE 1607 for
proper duplex switching.
1. Set up a conversation to a station in a room (office) with normal ambient
noise level.
2. Press down the microphone cut-off switch (privacy switch) on the initiating
station. The background noise from the receiving station should now be heard
in the loudspeaker of the initiating station.
3. Turn potentiometer R 56 on NFE 1607 card (on front of the card) until the noise
just disappears.
NOTE: This adjustment cannot compensate for noise from machinery, noisy
airconditioners etc.
C. Adjustment of warning tone level.
Adjust pot. meter R57 to a pleasant volume on the warning tone.
Page 24 of 77
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