Canon fax basic 2000 서비스 매뉴얼

6–17

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FACSIMILE SYSTEM

3.9

Relay Operations

The following describes operation of each of the relays.

• CML relay (Connect Modem to Line relay)

This relay is for switching between the facsimile and the telephone (hand-

set or extension telephone) that is the core function of the NCU board.

With regular relays, an instantaneous circuit interruption occurs at switch-

ing. If a regular relay is used for the CML relay, there is the possibility that

the

will malfunction because of this short break. For this reason,

an early make break relay designed to prevent short breaks is used for the

CML relay.

• H relay (Hook relay)

This relay is for enabling detection of the off-hook state on the telephone

(handset or extension telephone) during facsimile communications. As the

CML relay switches to the facsimile side during facsimile communica-

tions, the voltage is not supplied to the off-hook detection circuit. When

the H relay switches to the voltage terminal for off-hook detection, voltage

is supplied to the off-hook detection circuit to enable detection of the off-

hook state of the telephone even during facsimile communications.

• P relay (Pulse relay)

This relay is for generating the dial pulse (DP). A relay is used for prevent-

ing chattering or sparks.

• S relay

This relay is for shaping the pulse waveform that is generated by the P

relay. A relay is used for preventing chattering or sparks.

• R relay

This relay is exclusively for 230 V regions. It is used for sending signals to

when the R key is pressed. A photo-MOS relay

is used for this relay.