Source : Free On-Line Dictionary of Computing

Advanced Communication Function/Network Control Program
     
         (ACF/NCP, usually called just "NCP") The primary
        {SNA} {network control program}, one of the {ACF} products.
        ACF/NCP resides in the {communications controller} and
        interfaces with {ACF/VTAM} in the {host processor} to control
        network communications.
     
        NCP can also communicate with multiple hosts using local
        channel or remote links ({PU} type 5 or PU type 4) thus
        enabling cross domain application communication.  In a
        multiple {mainframe} SNA environment, any terminal or
        application can access any other application on any host using
        cross domain logon.
     
        See also {Emulator program}.
     
        [Communication or Communications?]
     
        (1999-01-29)