Matsushita Electric KX-TSC35MXW, Руководство по обслуживанию

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IC601 Pin 15 of IC601 Speaker.
3. Transmission/Reception switching
The comparison result between TX and RX outputs as a DC level
of Pin 25 of IC601.TX level is high ...... Pin 25 = Pin 21 - 6mV RX
level is high ...... Pin 25 = Pin 21 - 150mVComparator output is
connected to the attenuator control inside of IC601.
4. Voice detector
The output of the mic amp (Pin 10 of IC601) is supplied to Pin 13
of IC601 as a control signal for the voice detector.
5. Attenuator control
The attenuator control detects the setting of the volume control
through Pin 24 of IC601 to automatically adjust for changing
ambient conditions.
9.3.2. Telephone Line Interface
9.3.2.1. Circuit operation
- On hook
Q101 is open, Q101 is connected as to cut DC loop current and cut
the voice signal.
- Off hook
Q101 turns on thus providing an off-hook condition (active DC
current flow through the circuit) and the following signal flow id
for the DC loop current. T D101 Q101 Q108 R124 D106
D101 R
- The receiving signal flows:
TEL line Q101 C113 R125 C108 Q109 Q405 Q406
Headset Jack H/S SP
- The transmission signal flows
Mic Q421 Q424 C435 R437 Q108 Tel Line
9.3.3. Tone Detect
This circuit is used to sense the status of the line (busy tone or dial tone) during Auto Redial.
9.3.3.1. Circuit operation
D101 Q101 C201 R201 R205 Pin 5 of IC201 Pin 1 of IC201 D202 R208
Q201 Pin 43 of IC801
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