| 摘要 |
There are disclosed a method of call control (gapping) and a communications switching system in which such method is implemented, the system incorporating a call gapping arrangement for limiting the recurrence rate of successive call attempts for a particular type of call, for example to a national phone-in number, the arrangement comprising a clock (10) for determining a succession of call gapping intervals; a first up/down counter (18) having a limit N; a signal generator (11) responsive to the clock and coupled to the counter (18) to increment it by a value m each interval; a second up/down counter (21) having a limit M less than N, the counters (18,21) being responsive to call processing circuitry (14) to be decremented for each call attempt effected by the system; a comparator (15) responsive to the content of counter (21) becoming zero to inhibit the call processing circuitry (14) from allowing call attempts. The performance of the call gapping method is nearly ideal, and it can be left permanently operational. |
