The Free On-line Dictionary of Computing (30 December 2018):

framing specification

   A specification of the "protocol bits" that surround the
   "data bits" on a communications channel to allow the data to
   be "framed" into chunks, like start and stop bits in
   EIA-232.  It allows a receiver to synchronize at points along
   the data stream.

   (1995-01-13)