A total of 7,929 units were built, most of them for the French market, with a small number sold in Australia, Indonesia, and in other European countries.

The Mitra 15 was designed from the outset to complement and network with the most powerful French computer of the time, the CII Iris 80,[3] with which it was compatible.

[7] Intended for command and control of industrial processes such as scientific computing, the Mitra 15 was designed to be adaptable to very diverse fields of application, thanks to an innovative microprogramming system and a good price/performance ratio.

According to Le Monde, by 1974 the Mitra 15 had achieved revenue of 150 million francs; one eighth of the total sales of the CII, of which "30% was for remote processing" and "around 20%" for export.

It used a decentralized approach where Mitra 15 minicomputers acted as routers[9] and allowed for the transmission of data in small packets.

[10] Within the French PTT telecom network, the Mitra 15 was used with CII Iris 80s, due to its ability to handle a large number of interrupts.

[7] After 1976, because of the lowering of component prices, a fully electronic 2nd generation global telephone switch system, based on new integrated circuits, became affordable.

[11] As part of Plan Calcul, tt was then decided to install computers, on an experimental basis, in 58 high schools.

On the launch pad, the Mitra 15, associated with an Intel Frontal Table Image (FTI),[clarification needed] controlled, among other functions, the ignition sequence.

CII was handicapped by its 1974-1976 merger with Honeywell-Bull, who were more centered on traditional business computing, and by the abandonment of Unidata, which caused the termination of orders from Siemens.

[15] The Mitra 15 mini-computer, a mainstay since 1971 of its distributed computing strategy, was then sold to its shareholder Thomson, who had been opposed for more than a year to the merger of CII with Honeywell-Bull, despite a special mediation mission.