Plexus Computers Inc was right to believe there was value in its imaging software, but did not get time to benefit, and its the successor firm, Plexus Software Inc, owned by Recognition Equipment Inc, that is beginning to clean up. The first major taker for its XDP Extended Data Processing imaging software, which was written to run under Unix, is with AT&T Co, which will market the package with its own Unix systems through systems integrators. The two companies will jointly work on industry-specific applications for the system, which uses optical storage, laser printers and optical scanners connected via local area networks such as AT&T’s StarLAN system. Primary target markets are federal and state governments, the health care business, pharmaceutical and insurance companies, and banks and Plexus is negotiating similar agreements for the software with Amdahl Corp and NCR Corp. Prices vary with configuration.