After working for Schlumberger and Intertechnique for some time, he formed the company R2E (Réalisation d'Études Électroniques) in 1971.

In 1973, thanks to François Gernelle and a team of engineers, his company created the Micral, the first non-kit microprocessor-based personal computer in the world.

It was created two years before the MITS Altair of Micro Instrumentation and Telemetry Systems arrived on the market.

André Truong Trong Thi resigned from Bull, and joined the company Normerel formed by J. R. Tissot, a former member of R2E management.

Normerel was in 1988 the third French computer maker after Groupe Bull and SMT Goupil.