13 CIRCUIT OPERATION (BASE UNIT_MAIN)General Description:(DSP, EEPROM) is a digital speech/signal processing system that implements all the functions of speech compression andmemory management required in a digital telephone.The DSP system is fully controlled by a host processor DSP. The host processor provides activation and control of all thatfunctions as follows.13.1. DSP (Digital Speech/Signal Processing: IC501)•••• DTMF Detection/GeneratorThe DTMF detection is implemented by the DSP system in software. The DTMF detection is performed during Record, Playback, and Line Monitoring modes of operation.When the DTMF data from the Handset is received, the DTMF signal is output.•••• Caller ID demodulationThe DSP implements monitor and demodulate the FSK signals that provide CID information from the Central Office.•••• Analog SwitchingThe voice signal from telephone line is transmitted to the speaker or the voice signal from speakerphone microphone istransmitted to the Telephone line, etc. They are determined by the signal path route operation of voice signal.•••• Block Interface CircuitRF part, LED, Key scan, Telephone line.13.2. EEPROM (IC611)Following information data is stored.•••• Settingsex: ID code, Flash Time, Tone/Pulse50KX-TG2448BXF / KX-TG2448BXS / KX-TGA254BXF / KX-TGA254BXS
