KX-TG8075RUJ, KX-TG8075RUS, KX-TG8075RUT, KX-TG8076RUS, KX-TG8076RUT, KX-TGA807RUJ, KX-TGA807RUS, KX-TGA807RUT, KX-TGA809RUS, KX-TGA809RUT - Panasonic Telephone Service Manual (repair manual). Page 8

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The base unit consists of base band controller, speech network, tel-line interface, EEPROM, RF module, linear regulator, crystal
and so on. Refer to Block Diagram (Base Unit) (P.7).

BBIC (U2) controls all functions of the base unit. This device includes all control circuits of the base unit for RF module, tel-line
interface, ADPCM codec, series regulator and so on. 

The power supply is generated by LM1117 voltage regulator (U2). 
U2 generates DC 3.3V voltage from DC 6V voltage of adaptor output. DC 3.3V is used for RF module & I/O port, DC 2.5V &
DC1.8V are used for the base band controller and the circumference circuits.

The TR circuit is used for speech network. The function of this connects tel-line interface and the base band controller.

The function of this connects tel-line and speech network. Also, the tel-line interface includes the ring detect circuit, caller-ID cir-
cuit.

This is 128K bits memory. The each kind of value to set-up at power-on, caller list memory, and so on are stored in this device.

Receiver part: RF signals induced at the antenna are extracted by the RF control interface. The RF signal to be selected is
demodulated into RX_DATA signals. And the signals are passed to the base band controller.
Transmitter part: The signal from transceiver chip-set is fed to the antenna through the RF power amplifier by control of the RF
control interface. And then this signal is radiated from antenna.
Logical part: The frequency to be used is generated in transceiver chip-set by control signals (CLK, DATA, ENABLE, SYRI) of
the RF control interface.