DuckCorp Dico

Found one definition

1.                 From The Free On-line Dictionary of Computing (19 January 2023):
                   
   
   
                   
                     
   FIR
      1. <electronics> Finite Impulse Response (filter).
      2. <standard> Fast Infrared.  Infrared standard from IrDA,
      part of IrDA Data.  FIR supports synchronous
      communications at 4 Mbps (and 1.115 Mbps?), at a distance of
      up to 1 metre.
      (1999-10-14)