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1. Main Connector; consisting of the following:
a. Pins 1 & 2: AC Power Input Terminals.
Connects to the AC terminals of the 24VAC Power Pack
supplied with the IRC-21
b. Pin 3: AC Ground Terminal.
It can be connected to the ground terminal of the 24V AC
Power Pack if required by local building codes.
c. Pin 4: Audio System Ground.
May be connected to shield of shielded-pair input cable. If
other end of audio cable shield is connected to a chassis ground,
this terminal may be left open.
d. Pin 5 & 6: Audio Input Terminals.
Balanced, differential input. One side may be grounded for
single ended input.
2. Input Range Selector.
With both switches in the upper position, the audio channel input level
range is 0.1 to 1.0 Vrms. With both switches in the lower position, the
input range is from 2 to 20 Vrms (suitable for speaker amplifier output
levels).
3. Signal Presence Indicator.
Indicates proper audio level when light blinks at the peaks of the sound.
UPC-21 Features
UPC-21
I
NSTRUCTION
M
ANUAL
Ultra Stereo Labs, Inc.
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IRP-20 Power Pack