The Collaborative International Dictionary of English v.0.48:

Telegraphy \Te*leg"ra*phy\, n. [Cf. F. t['e]l['e]graphie.]
   The science or art of constructing, or of communicating by
   means of, telegraphs; as, submarine telegraphy.
   [1913 Webster]

WordNet (r) 3.0 (2006):

telegraphy
    n 1: communicating at a distance by electric transmission over
         wire
    2: apparatus used to communicate at a distance over a wire
       (usually in Morse code) [syn: telegraph, telegraphy]

The Free On-line Dictionary of Computing (19 January 2023):

telegraphy

    A historical term for communication,
   either wired or wireless, using Morse code.  The term is
   used in contrast with telephony meaning voice transmission.
   Telegraphy is sometimes (somewhat incorrectly) referred to as
   "continuous wave" or CW transmission.

   (2009-11-24)