| 摘要 |
PURPOSE:To attain the effective use of a public communication line and to reduce the cost required for the installation of in the subscriber side, by providing a transmitting speed recognizing means informing the data transmitting speed to a monitoring means, and modulation/demodulation means corresponding respectively to the plural kinds of transmission speeds. CONSTITUTION:A central processing unit 1 selects a modulation/demodulation device corresponding to the transmission speed of a transmission data among the modulation/demodulation devices 6, 7, 8 at the transmission, and a communication controller 2 transmits an ER signal to rise the selected modulating/demodulating device based on the command. The ER signal monitor 4 turns on the circuit of the modulating/demodulating device 6 by receiving the ER signal. Thus, the circuit of the modulating/demodulating device 6 is operative for attaining transmission. A transmission speed recognizing section 10 detects the transmission speed of the receiving data at the receiving from the period of a clock pulse included in the receiving information. This is informed to the ER signal monitor 4 to rise the corresponding modulating/demodulating device 6. The receiving on the transmission speed is attained and even if the transmission of transmission/receiving is changed frequently, it responds automatically. |
