phone card vs calling card

phone card and calling card both are nouns.

Word	Noun	Adjective	Verb	Adverb
phone card	Yes	No	No	No
calling card	Yes	No	No	No

As nouns, phone card and calling card are synonyms defined as:

phone card and calling card: a card that is used instead of cash to make telephone calls

phone card (noun)	calling card (noun)
a card that is used instead of cash to make telephone calls	a distinguishing characteristic or behavior
	a printed or written greeting that is left to indicate that you have visited
	a card that is used instead of cash to make telephone calls