<s>
Irma	B-Device
board	I-Device
,	O
originally	O
spelled	O
IRMA	B-Device
board	I-Device
,	O
refers	O
to	O
a	O
brand	O
of	O
coaxial	O
interface	O
cards	O
for	O
PCs	B-Device
and	O
Macintosh	B-Device
computers	I-Device
used	O
to	O
enable	O
3270	B-Application
emulator	I-Application
programs	O
to	O
connect	O
to	O
IBM	O
mainframe	B-Architecture
computers	I-Architecture
.	O
</s>
<s>
IRMA	B-Device
boards	I-Device
were	O
used	O
to	O
connect	O
PCs	B-Device
and	O
Macs	B-Device
to	O
IBM	O
3274	O
terminal	O
controllers	O
.	O
</s>
<s>
IRMA	B-Device
boards	I-Device
supported	O
both	O
Control	O
Unit	O
Terminal	O
(	O
CUT	O
)	O
and	O
Distributed	O
Function	O
Terminal	O
(	O
DFT	O
)	O
mode	O
,	O
although	O
the	O
later	O
required	O
additional	O
software	O
–	O
DFT	O
mode	O
supported	O
multiple	O
simultaneous	O
mainframe	B-Architecture
sessions	O
.	O
</s>
<s>
IRMA	B-Device
boards	I-Device
were	O
invented	O
by	O
Technical	O
Analysis	O
Corp	O
.	O
(	O
TAC	O
)	O
,	O
acquired	O
by	O
Digital	O
Communications	O
Associates	O
,	O
Inc	O
.	O
(	O
DCA	O
)	O
who	O
manufactured	O
and	O
marketed	O
the	O
Irma	O
products	O
from	O
1982	O
on	O
.	O
</s>
