Irma board
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.
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.