Call processing monitor system

Claim 1

A call processing monitor system for dynamically verifying the operation of a telephone switching center including initialization means, a plurality of originating lines each connected to said switching center and a plurality of terminating lines each connected to said switching center, said call processing monitor system comprising: means for selecting one of a plurality of said originating lines, said selecting means operated in response to said initialization means; dial tone detection means connected to each of said plurality of originating lines and operated to detect application of dial tone by said switching center; second means for selecting digit values representing a telephone directory number operated in response to said operation of said dial tone detection means; means for transmitting said digit values connected to said second selecting means; means for sequencing said digit values for transmission connected to said transmission means; ring detection means connected to said terminating line and operated to detect a complete path from said originating line to said terminating line through said switching center; answer means connected to said ring detection means and operated in response to said operation of said ring detection means to produce a signal representing an off-hook condition; test tone generation means connected to said answer means and operated in response to said off-hook condition to produce a test tone of a particular frequency; delay means connected to said answer means and operated in response to said off-hook condition to connect said generated test tone to said terminating line; test tone detection means connected to said originating line for detection of said complete path through such switching center whereby a first output signal is produced representing the detection of said complete path; timing means connected to said initialization means and to said test tone detection means, said timing means operate to time a predetermined interval whereby upon expiration of said interval a second output signal of a first characteristic is produced and alternatively for detection of said test tone a second output signal of a second characteristic is produced; threshold counting means connected to said timing means and operated in response to a plurality of second output signals of a said first characteristic to detect a consecutive accumulation of said second output signals whereby a third output signal is produced representing said consecutive accumulation attaining a predetermined threshold limit; and latching means connected to said threshold counting means and operated in response to said third output signal to produce a fourth output signal representing an indication of consecutive failures of said call processing monitor system.