Abstract: A cleaning system retrieves a telephone number from a telephone number list to regard as a called party number and sends a SETUP message to the network, in which a SPEECH or an AUDIO is designated as a bearer capability. In case that an ALERTING or CONNECT message is sent back from the network, the system sends a DISCONNECT message to the network immediately to perform a clear sequence and determines the telephone number effective. In case that a DISCONNECT message is sent back from the network as a result that a call has not been accepted, the system also performs a clear sequence immediately and determines if the telephone number should be treated as an effective number or a null number according to the cause content sent from the network.

Abstract: A credit status checking system for examining credit status of a customer immediately and easily, by utilizing a stored customer telephone number through a computer system performing the examining procedure automatically is disclosed. A telephone number examining apparatus connected with ISDN as a subscriber terminal processes circuit-switched call control procedures defined in the ITU-T recommendation Q.931 as a calling terminal. A database manager searches a customer file corresponding to a customer ID input by a customer through an automated transaction machine, retrieves a telephone number contained in the customer file, and transmits the number to the telephone number examining apparatus. The telephone number examining apparatus sends a SETUP message including an unrestricted or a restricted digital information in a bearer capability information element to the network where the telephone number received from the database manager defined as a called party number.

Abstract: A cleaning system retrieves a telephone number from a telephone number list to regard as a called party number and sends a SETUP message to the network, in which an unrestricted digital information is designated as a bearer capability. In case that an ALERTING or CONNECT message is sent back from the network, the system sends a DISCONNECT message to the network immediately to perform a clear sequence and determines the telephone number effective. In case that a DISCONNECT message is sent back from the network as a result that a call has not been accepted, the system also performs a clear sequence immediately and determines if the telephone number should be treated as an effective number or a null number according to the cause content sent from the network.

Abstract: A cleaning system for a telephone number list is capable of automatically perform deleting process for null telephone number and updating process for re-writing telephone number list.