| 摘要 |
A device and a method for directing incoming calls from a single input telephone line to either a facsimile machine, a data modem, or a telephone is provided. An incoming call is initially assumed to be a voice call, with ample time provided for allowing a person to answer the phone. The device and method provide for "isolating" both a facsimile machine and a data modem until after a predetermined delay period, thus preventing them to answer the call. The delay period may, for example be three to seven rings, thus allowing ample time for an operator or answering machine to answer the call and not cause any serious inconvenience to the caller. If a person or answering machine has not answered the call within the delay period, an off-hook condition is simulated to the input telephone line, thus "answering" the call. The signal on the input telephone line is then detected. If the signal includes a DTMF digit, various functions are performed including resetting internal variables. If a facsimile handshake signal is detected, the facsimile machine is rung with a ring simulator. The facsimile machine can then read the incoming handshake signal and proceed in a conventional fashion. If, however, neither of these two signals are detected, and a telephone answering device has not answered the call, the data modem port is rung with the ring simulator. The data modem will then begin receiving the transmitted signal in a conventional fashion. If the call is answered during the delay period provided by the invention, and the transmission is a facsimile handshake signal, the call is automatically transferred to the waiting facsimile machine. If a person answers the telephone during the delay period and the call is a data modem transmission, the person must enter DTMF digits by pressing the appropriate digits on the touch-tone keypad of the telephone. The call will then be transferred to the data modem.
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