Earlier e-mail switching software from Soft-Switch, Wayne, PA, that provided an e-mail backbone for organizations with diverse e-mail systems. It switched between more than 50 messaging protocols using X.400 as the common denominator and ran on IBM mainframes, AIX and a Unix-based Data General computer. Soft-Switch became a division of Lotus in 1995, which was itself acquired by IBM later that year. See also softswitch.