METHOD AND APPARATUS FOR SWITCHING A CLOCK SOURCE FROM AMONG MULTIPLE T1/E1 LINES WITH USER DEFINED PRIORITY

摘要

A clock selection controller is shown which allows a user to assign a priority scheme to recovered clock signals obtained from communication facilities. The clock selection controller also receives a plurality of alarm signals corresponding to the communications facilities for each of the recovered clock signals. The clock selection controller then automatically selects, for output as a reference clock signal, the highest priority clock input available for which the corresponding alarm signals are inactive. In the absence of an available clock input in the priority scheme, the processor selects a free running clock input.