| 摘要 |
PURPOSE:To make easy the identification by a pair of signal lines connecting the terminal unit, by taking the constitution that the terminal unit called is identified through the detection of a given response signal from the terminal unit with CPU and catching the counter value of the response signal. CONSTITUTION:CPU 1 and a plurality of terminal units 2a, 2b...2n are connected with a pair of signal lines L1 and L2 and the data delivery is made between CPU 1 and the units 2a to 2n. The units 2a to 2b are provided with the control circuit 203, switching element 205, voltage stabilizing circuit 201 and signal receiver 202. Further, CPU 1 is provided with the control circuit 107, switching element 103 and signal receiver 106, and the call signal fed from the units 2a to 2n with CPU 1 is detected, the selection signal is delivered to the units 2a to 2n, and the value is counted. The units 2a to 2n count the selection signal and deliver the response signal to CPU 1 when it is in agreement with the specific number predetermined. CPU 1 identifies the units 2a to 2n called from the specific response signal. |
