| 摘要 |
PURPOSE:To attain connection between subscribers occupying plural number of terminals by providing a call identification signal generator of a data system and a call type identification trunk to an exchange and transmitting/receiving call type identification information by means of an in-slot signal to utilize a conventional telephone network. CONSTITUTION:A subscriber 1 transmits a data system calling signal to a subscriber circuit 3 by using a control signal bit on a subscriber line 2. The control signal bit is separated from the in-slot signal at an interface section 4 and transmitted to a control signal transmitting and receiving section 5. A control signal is analyzed at the transmitting and receiving section and as a result, it is discriminated as a data system calling, the data system calling identifying signal generator 6 forms the data call identification signal by the in-slot signal and transmits it to a data channel terminal 8b. When the called party is discriminated as a subscriber at an incoming exchange, the incoming call is connected to the call type identification trunk 20 so as to identify the telephone system call/data system call. When the call is the telephone system call, it is connected to a terminal 18a, and when data system call, it is connected to a terminal 18b. The data system call reaches the called party 11 after being loaded on a data channel on the subscriber line 12 by a multiplex circuit 17. |
