Panasonic KX-TH1211B Service Manual page 9

4.2.3. Signal Flowchart in the Radio Parts
Reception
A voice signal from TEL line is encoded to digital data "TXDATA" by DSP (IC501) in a base unit.
Then TXDATA goes to RF PART, and it's modulated to 1.9 GHz. The RF signal is amplified and fed to a selected antenna.
As for a handset RF, RF signal is received in two antennas.
RFIC (IC701) compares RF signal levels and selects the antenna to be used. Then RFIC down-converts to 864 kHz IF signal
from RX signal in the selected antenna, and demodulates it to digital data "RXDATA".
DSP (IC501) converts RXDATA into a voice signal and outputs it to speaker.
Transmission
A voice signal from microphone is encoded to digital data "TXDATA" by DSP (IC501) in a handset.
Then TXDATA goes to RF PART, and it's modulated to 1.9 GHz. The RF signal is amplified and fed to a selected antenna.
As for a base unit RF, RF signal is received in two antennas.
RFIC (IC701) compares RF signal levels and selects the antenna to be used. Then RFIC down-converts to 864 kHz IF signal
from RX signal in the selected antenna, and demodulates it to digital data "RXDATA".
DSP (IC501) converts RXDATA into a voice signal and outputs it to TEL line.
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KX-TH1211B/KX-TH1212B/KX-TGA930T