Adjustments
The following adjustments are accessible either internally (refer to Figure
2) or from the underside of the US-2000, as shown in Figure 3.
Return Cancellation Adjustments (R187, R188)
Adjusted at the factory to cancel audio output that may be re-
flected from the line. There is a separate adjustment for each
channel. The Return Cancellation should only require adjust-
ment when the channel impedance or capacitance changes sig-
nificantly. To adjust one channel; connect powered speaker (set
for full volume), enable TEST SIGNAL on desired channel, and
adjust appropriate Return Cancellation to minimize signal volume
on the speaker.
Limiter Adjustment (R198)
Adjusted at the factory for 1 Vrms audio output to the line. If the
microphone input is higher than 4 mVrms, adjust the pre-amp
Limiter to reduce clipping of the audio output signal, if neces-
sary.
CONNECTOR PIN CONFIGURATIONS
Mono Headset Connector
Type: XLR-4M
Pin 1
Headset microphone low
Pin 2
Headset microphone high
Pin 3
Headphone high
Pin 4
Headphone low
Panel Microphone or Stereo Headset Connector
Type: NTRK-8F
Pin 1
Panel microphone low
Pin 2
Panel microphone high
Pin 3
12 VDC
Pin 4
Headset microphone high
Pin 5
Right headphone high
Pin 6
Right headphone low
Pin 7
Left headphone high
Pin 8
Left headphone low
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