1. In a communication system having a digital host computer and an instrument which generates a stream of serial digital outputs, a universal communication interface coupled between the host computer and the instrument, the interface comprising: a microprocessor having executive means for executing instructions entered by the host computer into the microprocessor, the instructions forming a set of distinct instructions; and a scratchpad memory for receiving and storing digital signals; wherein the executive means divides the scratchpad memory into a defined structure of at least one record in response to the receiving of at least one corresponding instruction having a selectable variable portion from the host computer, the selected variable portion determining the defined structure of the scratchpad memory and wherein digital signals, corresponding to the digital outputs from the instrument, are directed into and in conformance with the defined structure of one of the at least one record in response to a corresponding instruction from the host computer.