Canon fax basic 2000 서비스 매뉴얼

FACSIMILE SYSTEM

6–10

3.4

Line Signal Monitor

In the 

 is switched to

the telephone side in the same way as in a standby state so that the tele-

phone line is connected directly to the telephone. However, when the call-

ing party is a facsimile, the CML relay must be switched to facsimile for

reception, and so the CML relay is switched to the facsimile side according

to the signals arriving from the telephone line.

For this reason, a circuit (line signal monitor circuit) is made between the

CML relay and the H relay for monitoring the signals (CNG or 

that arrive from the telephone line. In the answering machine connection

mode, the signals are monitored to enable facsimile communications

immediately when the other party is a facsimile.

The line signal monitor circuit is divided into a primary side and secondary

side with a transformer provided as the boundary in the same way on the

facsimile side.

Fig. 6-9   Line Signal Monitor Circuit

B

MODEM

CML relay

CNG

CNG

CNG

CNG

"We are unavailable at the
moment to take your call."

Answering machine
message currently
being played back

Exchange

Off-hook

detection

circuit

CI detection

circuit

H relay

Line signal monitor circuit

To 2-wire/4-wire
conversion circuit

NCU board