Panasonic KX-TC1743B Service Manual page 50

Circuit Operation:
When the AC Adaptor is inserted into the unit, then the voltage is shifted by IC100, D101 and
power is supplied to the DSP.
The set can operate beyond point
13.5. Locator/Intercom Mode
1. When the base unit LOCATOR/INTERCOM button is pressed, a call
monitor signal (intercom sound) is output from pins 29 and 31 of
IC201. Thus a monitor tone is heard from the speaker.
2. At the same time, flashing of the IN USE/CHARGE (LED202) is
obtained from pin 70 of IC201. This status is called "Intercom stand
-by".
3. The receiving signal flows:
RF pins 29 and 31 of IC201
in the circuit voltage diagram.
SP
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