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

ARQ
       Automatic Re-transmission reQuest (MODEM)


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

Automatic Repeat Request
ARQ

    (ARQ) A modem error control protocol in
   which the receiver asks the transmitter to resend corrupted
   data.

   (1995-11-14)