Data communication system and method

Incoming data which is required to be passed to a desired storage location under the control of a processor is received by a store prior to being passed to a serial communications controller. The store is preferably a FIFO store and stores the data at an incoming data rate determined by the incoming transmission line data rate and feeds the data to the serial communications controller at a higher data rate under the control of a clock generator which is energised by control circuitry only when the data may be accepted by the serial communications controller. The processor can therefore control the serial communications controller to cease to process incoming data, which data is then stored until the processor can spare the time to recommence processing the incoming data.