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12 CIRCUIT OPERATION (BASE UNIT_MAIN)
General Description:
(DSP, Flash Memory) is a digital speech/signal processing system that implements all the functions of speech compression,
record and playback, and memory management required in a digital telephone answering machine.
The DSP system is fully controlled by a host processor DSP. The host processor provides activation and control of all that
functions as follows.
12.1. DSP (Digital Speech/Signal Processing: IC501)
• • • • Voice Message Recording/Play back
The DSP system use a proprietary speech compression technique to record and store voice message in Flash Memory.
An error correction algorithm is used to enable playback of these messages from the Flash Memory.
• • • • DTMF Detection/Generator
The DTMF detection is implemented by the DSP system in software. The DTMF detection is performed during Record, Play
back, and Line Monitoring modes of operation.
When the DTMF data from the Handset is received, the DTMF signal is output.
• • • • Synthesized Voice (Pre-recorded message)
The DSP implements synthesized Voice, utilizing the built in speech detector and a Flash Memory, which stored the vocabulary.
• • • • Caller ID and Call Waiting CID demodulation
The DSP implements monitor and demodulate the FSK signals that provide CID information from the Central Office.
• • • • Analog Switching
The voice signal from telephone line is transmitted to the speaker or the voice signal from speakerphone microphone is
transmitted to the Telephone line, etc. They are determined by the signal path route operation of voice signal.
• • • • Block Interface Circuit
RF part, LED, Key scan, Speaker, Microphone, Telephone line, LCD.
12.2. Flash Memory (IC601)
Following information data is stored.
• • • • Voice signal
ex: Pre-recorded Greeting message, Incoming message
• • • • Settings
ex: message numbers, ID code, Flash Time, Tone/Pulse
KX-TG5671S / KX-TG5672B / KX-TG5673B / KX-TGA560S / KX-TGA560B
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Troubleshooting
