| 摘要 |
A digital bus system for the transmission of pulse code modulated speech and control data between a common multiplexer and a multiplicity of line circuits in a telecommunications system. In the past the line circuits were multiplexed directly onto a common bus so that failure of one line circuit could result in the balance of the line circuits on that bus being rendered unserviceable. In the present system each line circuit is coupled over a separate data line to a pair of multiplexers so that failure of any one line circuit does not affect the operation of the others. Under normal operation one of the multiplexers functions as the primary and the other as a secondary. However, should the primary multiplexer fail, the secondary will take over upon actuation of a single control signal from a controller.
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