telephoner vs talker

telephoner and talker both are nouns.

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

As nouns, talker is a hypernym of telephoner; that is, talker is a word with a broader meaning than telephoner:

telephoner: the person initiating a telephone call
talker: someone who expresses in language; someone who talks (especially someone who delivers a public speech or someone especially garrulous)

Other hypernyms of telephoner include speaker, utterer, verbaliser, verbalizer.

telephoner (noun)	talker (noun)
the person initiating a telephone call	someone who expresses in language; someone who talks (especially someone who delivers a public speech or someone especially garrulous)