Source : Free On-Line Dictionary of Computing

Synchronous Data Link Control
     
         (SDLC) An {IBM} {protocol}.
     
        A discipline conforming to subsets of the {ADCCP} of {ANSI}
        and the {HDLC} of the {International Organization for
        Standardization}.  SDLC manages synchronous, code-transparent,
        bit-serial communication which can be {duplex} or
        {half-duplex}; switched or non-switched; {point-to-point},
        {multipoint}, or loop.
     
        Compare {Binary Synchronous Communication}.
     
        (1995-03-22)