calling card

noun

• 1a card bearing a person’s name and address, sent or left in lieu of a formal social or business visit.
• an action by which someone or something can be identified:a dog whose calling card is a savage nip at the nearest ankles

• 2a card that allows the user to make telephone calls from any phone and charge the cost to their home telephone number.
• a prepaid card that allows the user to make telephone calls up to a specified value.