Sanyo SFX-110 Service Manual page 52

(F) NCU
Detailed Explanation of Network Control Unit (NCU)
cCML relay
The CML signal sets high, and output of Q301 (C) sets low (ON) and energies relay CML.
DP relay
The DP signal sets high, and output of Q302 (C) sets low (ON) and energies relay DP.
a) Transmission (Dialing by telephone)
1) When the telephone handset is lifted, photo-coupler (PC301 ) is turned on. The HS/LOOP signal is set to high.
2) Pressing the START switch on the operation panel energies relay CML and DP.
3) A contact on relay CML connects the telephone line to the Facsimile.
4) At the end of transmission relay CML and de-energized.
5) The telephone is connected to the telephone line.
b) Automatic reception
1) The Receiver signal Detector receives the incoming call.
2) At this time photo-transistor in the photocoupler (PC302) is turned ON.
3) An output in PC302 (PCE) sets high, and ringing detect by GATE ARRAY IC (IC1 4).
4) The ringing signal is fed to the CPU (IC1 O) which in turn energizes relay CML and DP.
5) A contact on relay CML contacts the Facsimile to the telephone line.
6) At the end of transmission relay CML and DP are de-energized.
c) Manual reception
1) When the dialing tone (signal) is received by the Facsimile the telephone is lifted and communication between
both party's can commence.
2) The Receiver Signal Detector Circuit operates but the relay CML does not energize because the Receive
Mode is set to manual.
3) When the telephone handset is lifted, photo-coupler PC301 is turned on. The HS/LOOP signal is set to high.
4) Pressing the START switch on the operation panel energizes relay CML, DP.
5) A contact on relay CML connects the telephone line to the Facsimile.
6) At the end of transmission relay CML, DP are de-energized.
7) The telephone is connected to the telephone line.
d) Manual dialing
case of pulse dial
1) When the telephone handset is lifted, photo-coupler PC301 is turned on. The HS/LOOP signal is set to high.
2) The other party's dial number is entered into the CPU (IC1 O) using the numeric key pad with function keys.
3) The relay DP turns on and off according to the dial number entered into the CPU (IC1 O), to produce dial
pulses.(the dial pulse rate is set by using the numeric key pad with menu key)
4) Relay CML, DP are energized.
5) A contact on relay CML connects the telephone line to the Facsimile.
6) At the end of transmission relay CML, and DP are de-energized.
7) The telephone is connected to the telephone line.
case of tone dial (DTMF)
4) Relay CML and DP are energized.
5) A contact on relay CML connects the telephone line to the Facsimile.
6) The CPU (IC1 O) controls the MODEM circuit in order to generate the appropriate Tone Dial signal according
to the entered dial number.
7) Tone Dial signal is fed from the MODEM (IC1 O).
8) At the end of transmission relay CML and DP are de-energized.
9) The telephone is connected to the telephone line.
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