Brother International FAX-170 Service Manual - Page 40

POWER N4 BA10324F 1.. I N3 74HC4053F • 4 BAI0324 -2 3 74HC4053 4 BAI0324 NCU BAI0324F .. 6 TC35133F @-1 12 NI NJM386M Main PCB Circuit Diagram 415 ® Connector for the power supply PCB ®-1: CR1, recording head on/off relay ® 3-terminal regulator which eliminates unstabilized components of the +9V source to generate stabilized 5V source. • Connector for the NCU ®-1: Power for the NCU ®-2: Signals to the telephone ®-3: Signals from the telephone ® Analog signal selectors ®-1: Selects either input signals from the handset or those from the MODEM. ®-2: Selects either RL1 or RL2 signals inputted from the communications network. ®-3: Selects sound signals (e.g., alarm beeps, key clicks and ringer sounds) generated by the FAX engine, hands-free monitor signals, or voice playback signals. ® Analog signal selectors ®-1 Selects either signals gated by ®-2 or voice signals coming from the handset. ®-2 Selects either signals gated by ®-2 or voice playback signals. ®-3 Selects either signals gated by ®-2 or hands-free monitor signals. ® Amplifier circuit for signals outputted from the MODEM ® Analog front end IC which processes the analog I/O signals from/to the MODEM ® Amplifier & shaper circuit for signals inputted from the communications network. ® Telephone circuit for transmitting signals. III - 28