Panasonic KX-A142EXM - Page 57

20.3. Telephone Line Interface
<Function>
- Bell signal detection
- Clip signal detection
- ON/OFF hook circuit
- Audio circuits
Bell & Clip (: Calling Line Identification Presentation: Caller ID) signal detection:
In the standby mode, Q2 is open to cut the DC loop current and decrease the ring load.
When ring voltage appears at the TP3 (A) and TP40 (B) leads (when the telephone rings), the
signal is transferred as follows;
- A C25 R40 R45 IC5 C28 R47 C29 R49 IC8
(136) [CLIP]
- B C24 R39 R44 IC5 C28 R47 C29 R49 IC8
(136) [CLIP]
- A C2 IC1 IC8 (81) [BELL]
- B D2 D3 R1 IC1 IC8 (81) [BELlL]
ON/OFF hook circuit:
57
www.freeservicemanuals.info
1/2/2015
Digitized in Heiloo, Holland