Canon fax basic 2000 서비스 매뉴얼

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FACSIMILE SYSTEM

3.3

Detection of Calling Identification (CI)

The CI detection function detects the calling identification (CI) sent from

the

. Normally, when dialing is performed from the calling party,

the bell of the telephone on the incoming call side rings according to the CI

from the exchange.

The CI detection function is required for automatic reception by a facsim-

ile. When CI is detected, the facsimile automatically receives the docu-

ment.

The DC component of the CI arriving from the telephone line is cut by a

capacitor (C1). The signal is then half-rectified by two photocouplers, PC1

and PC2, respectively, and the waveform is shaped by IC1 and IC2. The

waveforms of each of these outputs (CI1 and CI2) are aligned by OR cir-

cuit IC3, and the resulting waveform is sent to the system controller on the

SCNT board as CIOR together with CI1 and CI2.

The system controller distinguishes that the signal is CI by the waveform

pattern of the arriving signal.

Fig. 6-8 CI Detection Circuit

NCU board

Off-hook

detection circuit

CML relay

To 2-wire/4-wire conversion circuit

IC1

IC2

PC1

PC2

CI2

CIOR

CI1

IC3