Irma board, originally spelled IRMA board, refers to a brand of coaxial interface cards for PCs and Macintosh computers used to enable 3270 emulator programs to connect to IBM mainframe computers.[1][2] IRMA boards were used to connect PCs and Macs to IBM 3274 terminal controllers.[3]

DCA Irma board for PCs (IRMA II ISA)

IRMA boards supported both Control Unit Terminal (CUT) and Distributed Function Terminal (DFT) mode, although the later required additional software–DFT mode supported multiple simultaneous mainframe sessions.[4]

IRMA boards were invented by Technical Analysis Corp. (TAC), acquired by Digital Communications Associates, Inc. (DCA) who manufactured and marketed the Irma products from 1982 on. DCA[1] of Alpharetta, Georgia, was acquired in 1994 by Attachmate of Bellevue, Washington.

A board with all the capabilities of that which would eventually be called IRMA was originally developed in-house by Amdahl Corp in 1977, but it was not actively marketed by Amdahl.[citation needed]

See also



  1. ^ a b DCA Planning for Upcoming Era of Interactive Communications
  2. ^ Dong, Jielin (2007). Network dictionary. Saratoga, Calif.: Javvin Technologies, Inc. p. 262. ISBN 978-1-60267-000-6. OCLC 228403413.{{cite book}}: CS1 maint: date and year (link)
  3. ^ Singer, John (22 January 1985). "PC Metamorphosis: 3270 Emulation". PC Mag. 4 (2). Ziff Davis, Inc.: 170. ISSN 0888-8507 – via Google Books.
  4. ^ Stephens, Mark (16 October 1989). "Mac Irma Cards to Run 5 Simultaneous Sessions". InfoWorld. 11 (42). InfoWorld Media Group, Inc.: 29. ISSN 0199-6649 – via Google Books.