A computer interface for a clinical chemistry analyzer has been implemented using an MOS microprocessor. The interface uses ANSCII serial data transmission, incorporates error detection and correction, and may additionally serve as a teleprinter driver. Several benefits resulted from the use of a microprogrammable processor. Design changes during the development cycle were easily accommodated, and different instruments or communications protocols may be accommodated by changing only the microprogram stored in an erasable, reprogrammable read‐only memory.