Calling card

Calling cards are often found in phone boxes in London advertising the services of call girls

Calling Card may refer to various object of the same name:

• Historically, a calling card was used socially to signify a visit made to a house if the occupant were absent; or as an introduction for oneself (to new neighbours as an example). In this sense they are also known as visiting cards. Business cards are evolved from this sort of calling card.
• calling card (crime) — a signature token or characteristic of a crime used by a serial criminal to taunt police, or to gain notoriety.
• Telephone card
• An advert, stuck to a phone boxes to advertise the services of a call girl. Also known as a tart card.