| 摘要 |
PURPOSE:To prevent the state of disabled communication by providing a device for detecting the start of transmission and a time supervising circuit to a transmission circuit section to detect earlier the stall state to the control of the software or the firmware. CONSTITUTION:In detecting an F pattern being the final character of one block by an F pattern detector 8 in a communication processing device controlling the semi-duplex communication system, the output of a flip-flop 13 and the output of the F pattern detector 8 are inputted to an AND circuit 14, to make the circuit 14 output and a timer 12 reset, then the output of the AND14 is delayed by a delay circuit 17 and the flip-flop 13 is also reset. When the software or the firmware of the communication processing device control section 1 is stalled and a multiplexer 6 cannot transmit the F pattern being the final character of one block due to bug or any other cause, a value preset to the timer 12 is overflowed. When the timer 12 overflows, an interruption start circuit 15 is started and the fault of transmission is informed to the communication processing device control section 1 by interruption. |
