The Collaborative International Dictionary of English v.0.48:

Telegraphist \Te*leg"ra*phist\, n.
   One skilled in telegraphy; a telegrapher.
   [1913 Webster]

WordNet (r) 3.0 (2006):

telegraphist
    n 1: someone who transmits messages by telegraph [syn:
         telegrapher, telegraphist, telegraph operator]