| 摘要 |
PURPOSE:To prevent wasteful dialing when the circuit is fully busy and to improve the use effeiciancy of the circuit by dialing the talk time in addition to the telephone number of destination, and letting the exchange register this information on the management table as a connection information and make the connection control according to this information. CONSTITUTION:When a caller dials special number 1XY which denotes call connection service from a telephone E, subscriber's exchange A identifies this 1XY and sends the second dial tone (SDT) to the telephone E. After recognizing the tone, the caller dials the telephone number of arriving side F and the talk time, for example, 30 minutes. The exchange A recognizes that line group C is necessary basing on the telephone number received, and make an access to management file G, retrieves the line management table recorded in the file G to know the line utilization situation, and if there is an idle circuit, connects the call and records a talk time. If there is no idle circuit, it checks the line scheduled to be idle,and inform the caller how many minutes later the telephone call is possible. |
