| 摘要 |
The selective response device in a modem comprises a DAA unit for interfacing a telephone line with a modem IC; a modem IC unit having a modulation/demodulation function, a signal detection function and a filtering function; a ring signal detector for detecting a ring signal of the DAA unit and applying it to a microcomputer; and a system control microcomputer for exchanging data with the modem IC, receiving the output signal of the ring signal detector and controlling an LED unit, an alarming unit and a speaker driving unit.
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