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 10

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The handset consists of Base Band Controller, charger, regulator, LCD, EEPROM, RF module, keypad, crystal, speaker ampli-
fier, speaker, earpiece, ringer & microphone, and so on.

BBIC (U7) controls all functions of the handset. This device includes all control circuits of the handset for RF module, LCD con-
troller, keypad interface, earpiece, microphone, ADPCM codec, switching and series regulator and so on.

The base unit supplies DC 6V power to the charger and the charger charges the batteries to use this power. The signal on the
charger circuit is generated when the handset is being charged, and this signal is used to control the charger circuit and for
automatic off-hook by cradle-off when an incoming call is coming.

The battery is (2.4V / 2 cell) directly supplied to switching regulator which is controlled by base band controller and step up the
DC 3.3V to the RF module & I/O port. DC 2.5V & DC1.8V are used for the base band and the circumference circuits.

This is 256K bits memory. The each kind of value to set-up at power-on, redial memory, speed-dialing 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.

The keypad consists of 12 dialing keys and 11 function keys.

U2 forms a audio power amplifier for speakerphone and ringer.