| 摘要 |
PURPOSE:To set the number of each key telephone system whenever a power supply is turned on to a main device by causing each key telephone system to share one data receiving/transmitting circuit and one chalk at the main device side, reducing the number of parts and providing switches corresponding to respective key telephone systems at the main device side. CONSTITUTION:When a power supply is turned on to a main device and starts its operation, a common control circuit 11 reads out contents of a memory circuit 12, and turns on switches 161-16N corresponding to 2-N telephone sets from the 161 switch with the aid of outputs 01, 02,...0n of the common control circuit 11. When these switches are turned on, the output (d) of the common control circuit 11 starts power supply and the transmission of telephone set number data. A telephone set control circuit 211 fetches and stores a telephone set number data (a) transmitted from the common control circuit 11 in its internal memory through a data receiving/transmitting circuit 131, switch 161 and data receiving/transmitting circuit 221 at the telephone set side, whereby the telephone number of a key telephone system 2 turns out to be (a). |
