Panasonic KX-TGCA20EX Service Manual page 15

In IC501, the carrier frequency is changing, and frequency modulated RF signal is generated.In IC501,RF signal is amplified,
and radiated from antenna. Handset detects the voice signal or data signal in the circuit same as the following explanation of
Receiver Block.
4.4.6.2. Receiver Block
The signal of 1900 MHz band (1881.792 MHz ~ 1897.344 MHz) which is input from antenna is input to IC501 as shown in Block
Diagram (Base Unit_Main)(P.8).
In IC501, the signal of 1900 MHz band is downconverted to 864 kHz signal and demodulated, as GAP (Generic Access Profile)
standard DECT frames. It passes through the decoding section burst switch controller where it separates out the frame
information and performs de-encryption and de-scrambling as required. It then goes to the DSP section where it is turned back
into analog audio. This is amplified by the analog front end, and goes to the TEL LINE Interface.
4.4.6.3. Pulse Dialling (for CX, HK, TU, TW, BX, UE, ML only)
During pulse dialling the hookswitch (Q141, Q142) is used to generate the pulses using the HOOK control signal, which is set
high during pulses. To force the line impedance low during the "pause" intervals between dial pulses, the PULSE_DIAL signal
turns on Q140.
KX-TGC210/KX-TGC212/KX-TGC213/KX-TGC220/KX-TGC222/KX-TGCA20
15