Cci-22H; Wire / Partyline Interface - Clear-Com ECLIPSE EASI-PICO MATRIX User Manual

7. CCI-22H

2 wire / Partyline interface

Power LED
The green "PL Power" LEDs indicate whether the interface channels are getting
+30 VDC power from the external party line to which they are connected.
Level Controls
The "Send" level controls affect the level of the audio signals from the Easi-PiCo
matrix to the external party line.
The "Recv" level controls affect the level of the audio from the party line to the
matrix. The level controls have a range of ±13 dB; they are normally set to the
midrange position.
Send and Receive Null Adjustment
In interfaces, it is necessary to null (minimize) the leakage of send from return
audio as much as possible when an external party line is placed in the matrix
environment. Ideally, there should be no portion of the talk signal in the listen
signal.
The CCI-22 features sophisticated built-in nulling circuitry, including a
test-tone generator and an accessory earphone. The earphone plugs into a phone
jack on the front panel. When the earphone is plugged in, it automatically
switches on a test tone and monitors the output of the null circuit.
Figure 1-39: CCI-22H Front diagram
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