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1.                 From The Free On-line Dictionary of Computing (19 January 2023):
                   
   
   
                   
                     
   Terminal Adapter
   TA
   Terminal Adaptor
      <networking, hardware> (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 Adapter 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 Adapter does not interoperate with a modem; it
      replaces it.
      [ISDN FAQ].
      (1994-10-03)