Data transmitting apparatus and method for executing both facsimile communication and data communication without suspending a communication line

摘要

A signal sending device (facsimile modem 66; step STA2) responds a call from a calling party and sends a first signal (CED signal) to the calling party. The first signal (CED signal) indicates that a non-voice terminal of the called party is connected to a communication line in response to the call from the calling party. A signal detecting device (facsimile modem 66; step STA3) detects a second signal (CNG signal) while the first signal (CED signal) is sent out from the signal sending device. The second signal (CNG signal) indicates that the calling party is a non-voice terminal. A mode switching device (CPU 61, data modem 65, I/O controller 67; step STA9) automatically changes communication mode from a facsimile mode to a data communication mode when the signal detecting device does not detect the second signal (CNG signal) while the first signal (CED signal) is sent out. A communication control device (CPU 61, facsimile modem 66, I/O controller 67; step STA11) continues detection of the second signal and changes the communication mode from the data communication mode to the facsimile mode whenever the second signal is detected.