SYSTEM FOR DETECTING ISDN LINE DISCONNECTION

摘要

PROBLEM TO BE SOLVED: To provide a system for detecting ISDN line disconnection at a low cost by which a terminal of a line connection opposite party can be identified without the connection between a line disconnection monitor and each terminal through permanent virtual circuit and without the need for registering a logical channel to an ISDN in the case of connecting the terminal to the ISDN. SOLUTION: The line disconnection detection system 1 is provided with a line disconnection sensing compatible terminal 4 that is connected by using a destination selection connection system of a D channel packet service of an ISDN 2 and with a line disconnection monitor 8, allows each line disconnection sensing compatible terminal 4 to send ID information with respect to its own terminal to the line disconnection monitor 8 so as to establish a logical channel 7, allows the line disconnection monitor 8 to recognize to which line disconnection sensing compatible terminal 4 is connected to each logic channel 7 on the basis of the ID information, reads whether or not interruption of the logic channel is normally finished on the basis of a received CI packet when receiving the CI packet sent from the ISDN 2, specifies a disconnected ISDN line 3 on the basis of the ID information corresponding to the logical channel 7 when no normally finished and informs a prescribed system about the result.