| 摘要 |
PURPOSE:To make it possible to switch a press-to-talk transmitter-receiver and duplex transmitter-receiver easily by a hook switch, selection switch, etc., interlocking with those transmitter-receiver as to a unit which switches the transmission- reception ystem of an interphone unit. CONSTITUTION:In press-to-talk mode, turning ON a press-to-talk switch switches contacts S2-1 and S2-2 to the (a) side and microphone-speaker 13 is connected to subordinate equipment X1 by way of amplifier A and selection switch 12. At the time of the duplex system, transmitter-receiver 15 is used and hook switches S1-1, S1-2 and S1-3 are switched to the (a) side. With selection switch S3-n ON, switch S3-n1 interlocks and is placed in an ON state. Consequently, subordinate equipment Xn is connected to transmitter-receiver 15 via amplifiers A and A2. Therefore, malfunction is eliminated since only operation characteristic to each system is required for switching. |
