Data communications switching device having multiple switches operating at plural selectable data rates

A large scale integrated circuit device is disclosed that can be used as a component in a variable bandwidth branch exchange system or for other applications utilizing programmable network switching. The device contains a plurality of duplex per line switches (PLS). Each PLS interfaces between serial signal streams which may operate at various rates. Date transfers are programmable to occur at variable times with reference to the information highway timing and are programmable in length. The device may be controlled and monitored by an external device, and can optionally transfer control and status information between an external control device and one or more station devices.