Source : Free On-Line Dictionary of Computing

tall card
     
         An expansion card for the {IBM PC AT}.  These can
        be larger than {IBM PC} or {IBM PC XT} cards because the AT
        case is bigger.
     
        When IBM introduced the PS/2 model 30 (its last gasp at
        supporting the {ISA}) they made the case lower and many
        industry-standard tall cards wouldn't fit.  This was felt to
        be a reincarnation of the {connector conspiracy}, done with
        less style.
     
        See also {short card}.
     
        [{Jargon File}]
     
        (1995-03-01)