a telephone which requires prepayment for calls via coins, calling cards, phonecard, or credit/debit cards.

A public (or private) telephone that accepts coins or encoded credit cards.

A payphone or pay phone is a public telephone, with payment by inserting money (usually coins) or a debit card (a special telephone card or a multi-purpose card) or credit card before a call is made. Some telephone companies have termed them, and tried (unsuccessfully) to get the public to identify them as "coin phones", because the term "pay phone" may imply that other phones are free.