| 摘要 |
PURPOSE:To simply attain the simultaneous communication through the use of the private branch exchange system by disconnecting each extension telephone set from an exchange at the simultaneous communication, supplying a call signal to them so as to supply scheduled voice information to telephone sets. CONSTITUTION:A start signal 16 is applied to a changeover control circuit 14 at the request of simultaneous communication the circuit 14 disconnects line 21-2n from lines 61-6n to connect them to a changeover circuit 11. A changeover circuit 10 is connected at first to a call signal circuit 12 to apply a call signal to an extension telephone set to ring a bell. A timer 15 is started at the same time as a call and when a set time is arrived, the circuit 10 drives the signal to switch the circuit 12 to a sound signal sending circuit 13. Thus, the content of notice is sent to extension telephone sets from the circuit 13 via the lines 21-2n. |
