| 摘要 |
PURPOSE:To secure a high-speed and easy transmission for various kinds of the inter-office information by installing the inter-office information generation circuit to the terminal telephone set to vary the loop current through the switch control of the relay element. CONSTITUTION:The intermediate tap of secondary winding 24 of the transmission side transformer of the terminal telephone set is connected to inter-office information signal generation circuit 34 via hook switch 30 and constant voltage circuit 32, and furthermore sound amplifier 38 is connected in parallel to circuit 34 via the emitter-collector conduction path of switching transistor 36. Circuit 34 incorporates the clock pulse oscillator and the counter, and the pulses corresponding to the information set up through the push-button or the like are counted by the counter. These counted pulses are then supplied to the base of transistor 36 to give control to the conduction. As a result, the loop current is varied to transmit the inter-office information signals. |
