Panasonic KX-TSC10HGW, Service Manual

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When the bell signal is input between T/R, the signal is outputted at the speaker via the
following path:
Tel line R1/C1 Pin 1 of IC2/Pin 8 of IC2 Pin 5 of IC2 PC1 SW1 Ringer
11.2. Line Interface
In talk mode, SW101 becomes ON and Q104 base becomes High, causing Q104 and Q102 to turn
on and line loop is established.
The loop current flows as follows: D101(+) Q102 Q108 R114 D103.
The pulse signal that switches ON/OFF is output from pin 39 of the CPU.
Q104 and Q102 switch the line loop ON/OFF, generating the dial pulse signal.
11.3. Telephone Line Interface
11.3.1. Circuit operation
- On hook
Q102 cuts the DC loop current and the voice signal.
- Off hook
Q102 turns on to go into off-hook condition and the following
signal flow is for the DC loop current.
T D101 Q102 Q108 R114 D103 D101 R
- The receiving signal flows:
TEL line Q102 C105 C401 R401 Q401 Q403 Q404
Speaker
- The transmission signal flows:
MIC C422 R423 C424 Q422 R428 C427 Q108
TEL line
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