Stratus Computer Inc’s decision to put Unix up on its fault-tolerant supermicros has won the Marlborough, Massachusetts company an agreement with AT&T Co under which the two will ensure compatibility between AT&T Definity PABXs and Stratus’ XA2000s. The two will develop a software interface between the two, designed to enable software developers to write applications combining the processing capabilities of the Stratus kit with the voice and data capabilities of the Definities, basing it on AT&T’s Adjunct Switch Application Interface under Unix.