| 摘要 |
PURPOSE:To eliminate the manual switching operation, by changing the call connection to the MODEM connection after receiving the push-button dial signal or the multi-frequency selection signal. CONSTITUTION:When a subscriber A gives a start to a central controller CC, a network controller NCU of a subscriber B is called out. The NCU through which the called subscriber B replies sends a reply back to a generak telephone exchange network T to secure a talking state between the subscribers A and B. When the switching is given to a data communication, the calling subscriber A supplies a switch command to the controller CC. The controller CC starts a push- button dial signal oscillator PBOST to transmit a switch code for the switching to the data communication. This signal is received at a push-button dial signal receiver PBREC via the NCU of the subscriber B. Receiving this information, the controller CC switches a channel controller SPT to a MODEM device MD. When the exchange of information is over, the connection of the NCU is switched again to the controller SPT. |
