Irma board

{{short description|Early interface card for PCs and Macs}}

File:KL DCA BS0017.jpg

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.[https://books.google.com/books?id=rDwEAAAAMBAJ&dq=irma+board&pg=PA43 DCA Planning for Upcoming Era of Interactive Communications]{{Cite book|last=Dong|first=Jielin|url=https://www.worldcat.org/oclc/228403413|title=Network dictionary|date=2007|publisher=Javvin Technologies, Inc|isbn=978-1-60267-000-6|location=Saratoga, Calif.|pages=262|oclc=228403413}} IRMA boards were used to connect PCs and Macs to IBM 3274 terminal controllers.{{cite journal|last=Singer|first=John|date=22 January 1985|title=PC Metamorphosis: 3270 Emulation|url=https://books.google.com/books?id=l9C7NnwCf1gC&pg=PA170|journal=PC Mag|publisher=Ziff Davis, Inc.|volume=4|issue=2|page=170|issn=0888-8507|via=Google Books}}

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.{{cite journal|last=Stephens|first=Mark|date=16 October 1989|title=Mac Irma Cards to Run 5 Simultaneous Sessions|url=https://books.google.com/books?id=nDAEAAAAMBAJ&pg=PA29|journal=InfoWorld|publisher=InfoWorld Media Group, Inc.|volume=11|issue=42|page=29|issn=0199-6649|via=Google Books}}

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 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.{{fact|date=June 2020}}