| 摘要 |
PURPOSE:To enable the construction of the push button type telephone without requiring the main device by connecting the communication lines of a plurality of the push button type telephones to the control lines in parallel and making the push button type telephones compact and large number of telephone production possible. CONSTITUTION:There are accommodated a line CO-1 to k in which to the push button type telephone KT-i, other telephone is connected in parallel, an internal communication line INT-1 to l, and a control line CL and provided with a data transmission and receiving circuit T-i and R-i, a control circuit having a communication line INT empty condition mimorizing function CC-i, a communication switch SW-i, and a telephone circuit NW-i. Based on the internal communication line number specifying information and the partner telephone specifying information, the control circuit CC-i supplements the vacancy of the communication line. In accordance with the data transmission and receiving circuit, the data necessary for the relative communication is exchanged and the internal communication line is connected to the telephone circuit by the communication passage switch. |
