| 摘要 |
The doorphone communicating apparatus and method using a telephone includes a first relay for connecting a telephone and a line, a second relay for connecting the telephone and the line of an outer doorphone, a ring detector for discriminating a reception signal, a current detector for detecting the hook on/off of the telephone, a DTMF decoder for decoding a DTMF signal, a microcomputer for generating a tone generating signal, a door opening signal, and the control signal of the first and second relays, and a tone generator for generating a tone signal according to the control signal of the microcomputer, thereby enabling the communication using a tlephone.
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