| 摘要 |
PURPOSE:To detect trouble occurring to a toll board connection circuit on an SR system, by calculating an incomplete call rate from the counted values of the frequency of connection requesting from a switchboard to a toll board and the number of aborted calls, and then comparing it with a predetermined threshold value. CONSTITUTION:A subscriber telephone 1 is connected to the toll board 5 by a switchboard 2 through a circuit 4. A controller 6 is provided with counters 7 (CNTA) for the frequency of connection requesting and counters (CNTB) 8 for the number of aborted calls corresponding to circuits; when the switchboard calls the toll board through one circuit, the counter 7 corresponding to the circuit counts the frequency and the counter 8 also counts the frequency of incomplete connection due to abandonment on the way. The incompletion rate (CNTB/CNTA) within a time set by a timer 9 is calculated and compared with a threshold value set in a threshold value register 12 by a comparison part 13, and when the incompletion rate is large, it is judged that circuit trouble occurs. |
