Clock signal generation apparatus for use in an access subsystem

Abstract

An apparatus generates a set of a reference clock pulse and a reference frame pulse signals (RCPS and RFPS) for use in an access subsystem processor of an electronic switching system. At first, a set of a clock pulse and a frame pulse signals (CPS and FPS) generated from a processor associated with the apparatus is received and converted into a converted set of a RCPS and a RFPS. Next, a functional fail signal is obtained based on processor and signal status information from the link processor. Finally, the converted set of the RCPS and the RFPS, converted sets of RCPS's and RFPS's issued by the remainder of N local data link processors in each link module and converted sets of RCPS's and RFPS's from the subsystem processor are received and processed to generate a predetermined converted set of a RCPS and a RFPS as the set of the RCPS and the RFPS at an initial time regardless of the functional fail signal, and select one of the converted sets of the RCPS's and the RFPS's after the initial time in response to the functional fail signal to thereby provide the selected converted set of the RCPS and the RFPS as the set of the RCPS and the RFPS.