Source : Free On-Line Dictionary of Computing

V.90
     
         An {ITU-T} {standard} {modem} serial line
        {protocol} allowing download speeds of up to 56 {kbps} with
        upload speeds of 33.6 {kbps}.  {V.90} modems are designed for
        connections that are digital at one end and have only one
        digital-to-analogue conversion.
     
        As of 1998-02-06 the V.90 standard, formerly called V.pcm, has
        been given final approval by {ITU-T}.  On 1998-10-27 the ITU-T
        announced that approval of the V.90 standard was completed.
        Interoperability testing is complete or in progress for
        several modem manufacturers.  The V.90 standard reconciles two
        competing standards, {X2} and {K56flex}.
     
        The {ITU-T} has initiated the approval process for a new
        all-digital version of the protocol, to be known as {V.91}.
     
        {ITU Press Release 98-04
        (http://www.itu.int/newsroom/press/releases/1998/98-04.html)}.
        and {NP-3
        (http://www.itu.int/newsroom/press/releases/1998/NP-3.html)}.
     
        (1999-01-25)