Multistage digital cross connect with synchronized configuration switching

摘要

A digital cross connect comprises plural switching stages. Each stage has plural switches which receive plural frames of time multiplexed input data and which switch the data in time and space. Configurations of the switches change in frame synchronization at the start of a synchronized data frame. Both the configuration data and a frame clock may be propagated through the plural stages from a master switch. First and last stages of the digital cross connect may be implemented on common chips having two framing time bases. Data may be aligned to a global frame clock and interchanged using a single random access memory in a time slot interchanger. The write address to the random access memory is generated from a local frame counter keyed to the input data frame while a read address is transformed from a global frame counter.