Canon fax basic 2000 サービスマニュアル

FACSIMILE SYSTEM

6–2

1. INTRODUCTION

This chapter describes the functions of the main printed circuit boards used

on a facsimile.

Mainly, the following printed circuit boards are used:

• SCNT board for controlling the entire facsimile system

• NCU board that acts as the facsimile’s interface with the telephone

line

• OPCNT board that performs detection of button operations or LCD

display

• Power supply unit that supplies the required voltages to each of the

printed circuit boards from the AC power supply for household use

• G4CNT board that controls the G4 facsimile communications system

Generally, these printed circuit boards are connected mainly to the SCNT

board.

In addition to these printed circuit boards, there are also the PCNT board

and driver board. The PCNT board supplies high voltage for driving LBP

printers, and the driver board groups together the 

 for driving the

various motors on a BJ printer. These boards are sometimes integrated into

a single board depending on the model of facsimile or sometimes not pro-

vided on the facsimile.

Fig. 6-1   Wiring Diagram

Telephone line

To power outlet

Power supply

unit

OPCNT

board

DRIVER

board

SCNT board

PCNT

board

NCU board

or

G4CNT board