| 摘要 |
<p>PURPOSE:To simplify the device and to reduce the cost, by controlling the 1st count means in a main device and the 2nd count means in each telephone set are made to be synchronizing. CONSTITUTION:Counter circuits 4, 10 are activated with a basic clock pulse of the same timing from clock pulse generating circuits 5, 11. When a pulse indicating the state of count of the circuit 4 is applied to a start pulse train generating circuit 1, start pulse trains of a plurality of bits of constitution predetermined from the output are formed and transmitted to a telephone set via a transmission line 13. The pulse trains are received at a start pulse generating circuit 7 and the counter circuit 10. The circuit 10 starts a data output circuit 8. The transmitted data ME KT from the main device is transmitted to the circuit 8 via a control circuit 2 and transmission line 13, and outputted to a data output terminal. When the transmission is finished, the circuit 10 transmits an answer pulse train to an answer pulse train generating circuit 11. The circuit 11 transmits the answer pulse train to the main device via an output circuit 9 and a line 13.</p> |
