| 摘要 |
PURPOSE:To give a user whose have a communication in leased-line mode a selective connection communication mode upon occasion, by performing switching from leased-line communication to switching communication when a selective connection is requested from a terminal equipment and an exchange. CONSTITUTION:Terminal equipments 14 and 18 normally have a one-to-one leased-line communication through a communication channel 19' and a lased line 21. When the terminal equipments have a communication with the terminal equipment 17 (case 1), the terminal equipment 14 gives an advance notice of switching to the terminal equipment 17 through a communication channel. Then, the terminal equipment 14 sends an exchange mode switching request signal 23 to an exchange mode switching device 15 through a call control channel. The mode switching device 15 consists of a nonblock switch and switches a path to the communication channel between the exchange 16 and terminal equipment 14 on the basis of the switching advance notice signal 22 to send out a switching completion signal 24 to the terminal equipment 14 through the call control channel. On receiving it, the terminal equipment 14 performs prescribed call setting through the call control channel to start a communication sequence. |
