Description Of Circuits; Configuration - Toshiba GD-1210 Service Manual

4.2

Description of Circuits

4.2.1

Configuration

This section describes the function of each circuit.
The NCU board consists of the transformer, relay, analog switch and other peripheral devices. It con-
trols switching of the line path, generates the dial pulses, detects the line current and ring signal, and
monitors the line.
The NCU board is connected to CN501 on the FAX board. It can be also connected optionally to
CN502.
The description in this section is based on the NCU board for Line 1.
NA/TW models
NCU board
Line current
Lb
detection
circuit
Line
La
a2
External
telephone
b2
© 2006 - 2011 TOSHIBA TEC CORPORATION All rights reserved
T1
IC53
AG
~
DB1
- +
~
Dial pulse
generation
circuit
DC
consumption
circuit
1
0
1
0
RLY2
CML relay
Ring signal
detection
circuit
Fig. 4-3
4 - 3
IC53
IC51
IC52
Analog
switch
IC52
CNG signal
detection
circuit
GD-1210/1250/1270/1160/1260
REVA
REVB
TXOUT
RXIN
ANSDET
LD
FAX board
ATT3DB
CML
CI
ELECTRICAL CIRCUITS
4