Dual rail time and control unit for a duplex T-S-T-digital switching system

Claim 1

In a duplex time-space-time switching system including first and second parallel switching networks, said switching system transmitting a plurality of PCM voice samples over each of said first and second switching networks from a first to a second telephone subscriber via subscriber interface equipment, each of said subscribers being connected to each of said first and second parallel switching networks, said switching system comprising: synchronization means; each of said parallel switching networks including: first and second buses connected to said subscriber interface equipment; first and second space switching means connected to said synchronization means; first and second originating time switching means connected respectively to said first and second space switching means, connected to said synchronization means and connected to said subscriber interface equipment via said first and second buses, each of said originating time switching means operating to switch said PCM voice samples from said subscriber interface equipment; first and second terminating time switching means, said first and second terminating time switching means being connected respectively between said first and second space switching means, and said subscriber interface equipment and connected to said synchronization means, each of said terminating time switching means operating to switch said PCM voice samples from said first and second space switching means to said subscriber interface equipment; each of said terminating time switching means including: memory means connected between said first and second space switching and said subscriber interface, said first and second memory means being interconnected so that said first and said second memory means are written into simultaneously in sequential time slots with said PCM samples transmitted via said first and second space switching means; gating means connected respectively between said first and second space switching means and each of said memory means of said first and second terminating time switching means, each of said gating means operating respectively in response to said memory means of said terminating time switching means to transmit said PCM samples from said first and second space switching means to said first and second memory means; said first and said second memory means further operating so that said PCM samples from said first space switching means may be switched through said second terminating time switching means to said subscriber interface equipment or alternatively said PCM samples from said second space switching means may be switched through said first terminating time switching means to said subscriber interface equipment; said switching system further including: said synchronization means operating to simultaneously control said operation of said first and second originating time switching means of said first switching network synchronously with said first and second originating time switching means of said second switching network; said first and second space switching means of said first switching network simultaneously operating with said first and second space switching means of said second switching network in response to said synchronization means and to said operation of each said first and second originating time switching means; and said first and second terminating time switching means of said first switching network simultaneously operating with said first and second terminating time switching of said second switching network in response to said synchronization means and to said operation of each said first and second space switching means.