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

F2F
       Frequency - Double Frequency


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

face-to-face
F2F

    (F2F, IRL) Used to describe personal
   interaction in real life as opposed to via some digital or
   electronic communications medium.

   (1997-01-31)