V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

DS2
       Digital Signal level 2, "DS-2"


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

DS2

    A DS level and framing specification for
   digital signals in the North American digital transmission
   hierarchy.  A DS2 signal uses 96 PCM channels and has a
   transmission rate of 6.31 Megabits per second, twice that of
   DS1C.

   (1995-02-07)