Source : Free On-Line Dictionary of Computing

Single Connection Attach
     
         (SCA, "Single Connector Attachment") A non-standard
        type of {SCSI} connector, used mostly by {OEM}s, which carries
        both power and data on one 80-pin connector.  SCA SCSI drives
        tend to be cheaper but use with standard SCSI cables requires
        an adaptor and external termination.
     
        {(http://www.pcmech.com/show/harddrive/152/)}.
     
        (2003-06-21)