| 摘要 |
PURPOSE:To reduce the number of wirings for the multi-station interphone by carrying out the conncetion control of the channel via the 1-chip microcomputer. CONSTITUTION:The picking up of the receiver of telephone 3 is detected by controller 5 comprising the microcomputer, and the dial tone is transmitted via the route of terminal 11, channel circuit 14 and speaker 16. When controller 5 receives the called subscriber's number from keyboard 7 via terminals 12-15, the idle channel is detected through terminals 3-5 to decide the channel to be used. At the same time, the channel information, the caller's information and the called subscriber's information are transmitted to channel B from terminal 1 via selection signal transmitter 9. In addition, the code of the channel to be used is transmitted from terminals 6-9 and then decoded via switch controller 12 to actuate channel selection switch 10. Thus, channel circuit 14 is connected to channels C-E. |
