KX-TG8421RUB, KX-TG8421RUN, KX-TG8421RUT, KX-TG8421RUW, KX-TG8422RUB, KX-TG8422RUN, KX-TGA840RUB, KX-TGA840RUN, KX-TGA840RUT, KX-TGA840RUW - Panasonic Telephone Service Manual (repair manual). Page 8

8

Base Unit consists of the following ICs as shown in Block Diagram (Base Unit) (P.7).

• DECT BBIC (Base Band IC): IC7

- Handling all the audio, signal and data processing needed in a DECT base unit
- Controlling the DECT specific physical layer and radio section (Burst Module Controller section)
- ADPCM code filter for speech encoding and speech decoding (DSP section)
- Echo-cancellation and Echo-suppression (DSP section)
- Any tones (tone, sidetone, ringing tone, etc.) generation (DSP section)
- DTMF receiver (DSP section)
- Clock Generation for RF Module
- ADC, DAC, timer, and power control circuitry
- PLL Oscillator
- Detector 
- Compress/Expander
- First Mixer
- All interfaces (ex: RF Power Amp, EEPROM, LED, Analog Front End, etc.)

• RF Power Amp.: IC801

- Amplifier for transmission and reception

• EEPROM: IC401

- Temporary operating parameters (for RF, etc.)

• FLASH MEMORY: IC421

- Voice Prompt (TAM) D/L Area
- ICM/OGM Recording Area

• Additionally,

- Power Supply Circuit (+3.0 V, +2.4 V, +1.8 V output)
- Crystal Circuit (10.368 MHz)
- Charge Circuit
- Telephone Line Interface Circuit