phototelegraph vs telegraph

phototelegraph and telegraph both are nouns.

Word	Noun	Adjective	Verb	Adverb
phototelegraph	Yes	No	No	No
telegraph	Yes	No	Yes	No

As nouns, telegraph is a hypernym of phototelegraph; that is, telegraph is a word with a broader meaning than phototelegraph:

phototelegraph: an apparatus for transmitting pictures by phototelegraphy.
telegraph: apparatus used to communicate at a distance over a wire (usually in Morse code)

Other hypernyms of phototelegraph include telegraphy.

phototelegraph (noun)	telegraph (noun)
an apparatus for transmitting pictures by phototelegraphy.	apparatus used to communicate at a distance over a wire (usually in Morse code)

phototelegraph (verb)	telegraph (verb)
	send cables, wires, or telegrams