Source : Free On-Line Dictionary of Computing

Terminal Adaptor
     
         (TA) Equipment used to adapt
        {Integrated Services Digital Network} (ISDN) {Basic Rate
        Interface} (BRI) channels to existing terminal equipment
        standards such as {EIA-232} and {V.35}.  A Terminal Adaptor is
        typically packaged like a {modem}, either as a {stand-alone}
        unit or as an interface card that plugs into a computer or
        other communications equipment (such as a {router} or {PBX}).
        A Terminal Adaptor does not interoperate with a {modem}; it
        replaces it.
     
        [ISDN {FAQ}].
     
        (1994-10-03)