| 摘要 |
PURPOSE:To attain the discrimination of the kind of a device to be called by analyzing a response signal transmitted from the device to be called. CONSTITUTION:First, a calling device 5 makes an automatic incoming connection request to the device 3 to be called via an exchange 1. The exchange 1 connects the device 3 to be called and a tone signal transmitter 2, from which a prescribed tone signal is transmitted to the device 3. Since the device 3 transmits plural kinds of tone signals, a tone detector 4 detects them and when the tone signal of a special kind is not detected, the detector 4 gives a request to the exchange 1 so as to connect mutually the device 3 and the calling device 5. On the other hand, when the detector 4 detects the specific tone signal, the detector 4 gives a request so as not to connect mutually the device 3 and the calling device 5. Then the calling device 5 identifies the kind of the device 3 through the combination of the tone signals transmitted from the device 3. |
