| 摘要 |
PURPOSE:To ensure the synchronism by utilizing a no-signal state when no data flows to a transmission line as an identifier representing the start and end of data. CONSTITUTION:A synchronizing circuit (d) provided to a communication control circuit (b) generates an output signal (q) representing the presence of a changing state of a data signal (p). A processor C continues to supervise the output signal (q) of the synchronizing circuit (d) to measure the time after the signal (p) on the transmission line (a) is lost, that is, the time when the output signal (q) of the synchronizing circuit (d) falls down. Further, even if the signal (p) disappears on the transmission line (a) after a prescribed time ts decided in advance is elapsed, the processor C decides the point of time as the timing for conducting the synchronism, and the mode is switched to the reception of data or the transmitting mode (r) from this point of time T. |
