| 摘要 |
PURPOSE:To simplify the constitution of the circuit part where the flashing control is given to the display element such as the lamp or the like by supplying the corresponding timing pulses to both the main wire and the extension circuit, and thus to simplify the overall constitution of the key telephone device of 3-paired line system. CONSTITUTION:In the key telephone device, main wire 1 and 2 are connected to talking crosspoint 5 via main wire circuit 3 and 4, and crosspoint 5 is connected to call- out crosspoint 8 via extension circuit 6 and extension call circuit 7. The state of circuit 3, 4 and 6 are givien to boss 500 in time division, and the necessary flashing period is given by lamp signal production circuit 400 and then delivered to output line 410 in the form of time division to be supplied in parallel to part 10B- 12B of each terminal circuit. Thus, the flashing is controlled for display elements 36-38 through downward control signal transmission lines 36-38. Circuit 3 performs the conventional function and also delivers the control signals to buses 501- 503 according to timing pulse 109 for calling, talking and holding each. |
