US 4,064,369 A · Method and apparatus for path testing in a time division multiplex switching network

Abstract

After marker functions have been performed to set up a network path during normal call processing, a continuity word is inserted into the path. The output of the path is coupled back to the input via a test multiplexer at the input to circulate the continuity word. A word is taken from the path being tested after circulation and is compared to the original continuity word, with identity of comparison being verification of continuity. Continuity test apparatus includes a continuity word register and a comparator. The comparator has inputs from the continuity word register and from the network output for the path being tested. The continuity word may be inserted in the path from an output access memory for maintenance and test words, having its output to the same multiplex lead as the output buffer memory. The continuity word may also be taken from the continuity word register, and from there supplied to a third input of the test multiplexer, and this input is enabled during the time slot of one frame to insert the continuity word. If the network includes access from a controller to input and output buffer memories, the continuity test apparatus may be omitted, and direct reading and writing of the buffer memories used to insert and extract the continuity word from the path being tested, and the comparison is then done in the controller. The test path may also be extended via TDM digital lines to a remote line switch, where the outgoing channel is coupled back to the incoming channel in response to continuity test commands.

Claims23

Dependent claims

Apparatus for testing path continuity through a time-space-time switching network of a communication switching system, in which paths through said switching network use time slots of time division multiplex recurring frames;

said apparatus comprising means to insert a continuity word into a path being tested, said path being the actual call path to be placed into service, means to couple output and input points of said path being tested to form a continuously circulating loop for said continuity word, comparison means having a first input coupled to input means to receive said continuity word independently of said path being tested, and a second input coupled to said path being tested, said comparison means being operative to supply a verify signal at an output responsive to the words received at said first and said second inputs being the same.

Apparatus for testing path continuity through a time-space-time switching network of a communication switching system, which uses time division multiplexing in time slots of recurring frames for handling information signals comprising digitally coded words, said switching network having an input side and an output side, there being a plurality of channels, with each channel having an input appearance on said input side and an output appearance on said output side, paths being selectively established through said switching network, with each path comprising means to couple information signals from the input appearance of a first channel to the output appearance of a second channel and also from the input appearance of said second channel to the output appearance of said first channel during each of said recurring frames;

said apparatus comprising means to insert and continuously circulate a continuity word into one of said paths being tested, said paths being the actual call paths to be placed into service, at said input appearance of said first channel, means coupling said output appearance of said second channel to said input appearance of said second channel, means coupling the output appearance of said first channel to said input appearance of said first channel, comparison means having first and second inputs and an output, means to supply said continuity word to said first input independently of said path being tested, means coupling a predetermined point in said path being tested to said second input, said comparison means being operative to supply a verify signal at said output responsive to receiving identical words at said first and second inputs, so that said verify signal indicates continuity for the transmission of said information signals through said path being tested.

A method for testing path continuity through a time-space-time switching network of a communication switching system, which uses time division multiplexing in time slots of recurring frames for handling information signals comprising digitally coded words, said switching network having an input side and an output side, there being a plurality of channels, with each channel having an input appearance on said input side and an output appearance on said output side, paths being selectively established through said switching network, with each path comprising means to couple information signals from the input appearance of a first channel to the output appearance of a second channel and also from the input appearance of said second channel to the output of said first channel during each of said recurring frames;

said method comprising the steps of inserting a continuously circulating continuity word into one of said paths being tested, said paths being the actual call paths to be placed into service, at said input appearance of said first channel, coupling said output appearance of said second channel to said input appearance of said second channel, coupling the output appearance of said first channel to said input appearance of said first channel, comparing said continuity word with a word from a predetermined point in said path being tested to supply a verify signal responsive to the compared words being identical, so that said verify signal indicates continuity for the transmission of said information signals through said path being tested.

Dependencies are inferred from the claim text.

Method and apparatus for path testing in a time division multiplex switching network

Life of this patent

Method and apparatus for path testing in a time division multiplex switching network

Life of this patent

Abstract

Claims23