| 摘要 |
PURPOSE:To implement data communication using a DTMF signal with a conventional radio communication equipment by receiving the DTMF signal outputted from a device implementing data communication by the DTMF signal, modulating the signal with a carrier having a frequency set optionally and outputting the modulated signal from an antenna as a radio wave. CONSTITUTION:The transmitter is provided with a DTMF signal input section 3 receiving a DTMF signal (dual tone multi-frequency signal), a modulation circuit 4 modulating the low frequency signal inputted from the DTMF signal input section 3 by an optional high frequency and outputting the modulated signal, and a transmission circuit 6 sending the modulated signal inputted from the modulation circuit 4 from an antenna 5 as a radio wave. When a DTMF signal outputted from a device 2 implementing data communication by the DTMF signal is inputted to the DTMF signal input section 3, the signal is modulated by a carrier having an optionally set frequency and the modulated signal is outputted as a radio wave. Thus, the data communication of the DTMF signal is implemented easily without use of a public telephone line. |
