A 16‐bit microcomputer has been coupled to an optical multichannel analyser (OMA). This paper describes the hardware interface which has been developed so as to permit the transfer of spectra in both directions, from the OMA into the RAM extension memory of the microprocessing system, and back from there into either one memory of the OMA. A few elementary circuit modifications of the OMA itself are required to allow that back transfer, and are also described. A brief outline of the software is given. The adjunction of the microcomputer to the OMA makes it possible to operate this instrument in a new mode: real time with optical integration and nevertheless without any baseline.