phoner vs telephoner

phoner and telephoner both are nouns.

Word	Noun	Adjective	Verb	Adverb
phoner	Yes	No	No	No
telephoner	Yes	No	No	No

As nouns, phoner and telephoner are synonyms defined as:

Other synonyms of phoner include caller-up, caller.

phoner (noun)	telephoner (noun)
the person initiating a telephone call	the person initiating a telephone call