| 摘要 |
PURPOSE:To surely control the start even in the case of simultaneous occurrence of incoming start and outgoing start CONSTITUTION:A call request signal 1 from a terminal outputs a call detection signal 3 by a call detecting circuit 2, and this signal is inputted to a power control circuit 5 through an OR circuit 4. Since light is not detected and synchronism is not settled with respect to a transmission/reception control signal at this time, a transmission control signal 11 and a reception control signal 12 generated by the free-running clock of a transmission/reception control circuit 10 for call are selected by a selector control circuit 13 and are sent as a transmission control signal 14 and a reception control signal 15. When light is detected by a light detecting circuit 16, a light detection signal 17 is applied to the selector control circuit 13, and as the result, the transmission control signal 14 is set to the untransmittable state, and the reception control signal 15 is switched to a reception control signal 20 from a transmission/reception control circuit 18 for communication. |
