| 摘要 |
PURPOSE:To receive the burst signal regardless of the amount of a transmission delay time, by providing a circuit controlling the start and end of communication, reception synchronism holding state discriminating circuit, counting circuit, etc. for reception enabling time setting to a central control device. CONSTITUTION:A gate 12 is opened with a signal 20 from a signal controlling circuit 9 and a signal 21 giving a transmission time at the request of communication start, a transmission circuit 5 is controlled, and a transmission burst signal 23 is transmitted to a two line type transmission line 3. In this case, a selection circuit 10 selects the signal 21 and gives it to a gate 11 to make a reception circuit 4 receptable for the time other than a transmission time. The reception burst signal received at the circuit 4 is inputted to a burst synchronism bit extracting circuit 6 and a synchronism discriminating circuit 8. In the circuit 6, a burst synchronism signal 15 is outputted at a counting circuit 7, where counting is made in synchronizing with the signal 15, and a signal 16 giving the reception time is outputted to the circuit 10 and a decode signal 17 is outputted to a circuit 8. In the circuit 8, when the signal 17 feeds a synchronism holding signal 18 to the circuit 10, the circuit 10 selects the signal 16 to give the reception time to circuit 4 accordig to the transmission delay time. |
