Source : Webster's Revised Unabridged Dictionary (1913)

Telephonic \Tel`e*phon"ic\, a. [Cf. F. t['e]l['e]phonique. See
   {Telephone}.]
   1. Conveying sound to a great distance.

   2. Of or pertaining to the telephone; by the telephone.

Source : WordNet®

telephonic
     adj : of or relating to telephony; "telephonic connection"