telephoner vs phoner

telephoner and phoner both are nouns.

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

As nouns, telephoner and phoner are synonyms defined as:

Other synonyms of telephoner include caller-up, caller.

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