Point-of-sale terminal

A payment terminal, also known as a point of sale terminal, credit card terminal, EFTPOS terminal (or a PDQ terminal in the United Kingdom), is a device which interfaces with payment cards to make electronic funds transfers.

There are various types of terminals available to merchants, although most have the same basic purpose and functions. They allow a merchant to insert, swipe, or manually enter the required credit/debit card information, to transmit this data to the merchant service provider for authorization and finally, to transfer funds to the merchant. Most newer models not only process credit and debit cards but can also handle gift cards, cheques, and so on. The majority of card terminals transmit data over a standard telephone line or a wired or wireless Internet connection. Some also have the ability to cache transactional data to be transmitted to the gateway processor when a connection becomes available; the major drawback to this is that immediate authorization is not available at the time the card was processed, which can subsequently result in failed payments. Remote wireless terminals can transmit card data using either cellular or satellite networks.

A merchant can replace the functionality of dedicated credit card terminal hardware using a terminal application running on a PC or mobile device, such as a smartphone. They usually work with dedicated hardware readers that can transfer magnetic stripe data to the application, while there are also some that also work with smart cards (using technology such as EMV), although this is rarely seen on smartphone readers. In case the necessary hardware is unavailable, these applications usually support manual entry of the card number and other data. In addition, more and more devices are beginning to offer built-in RFID or NFC technology to accommodate contactless or mobile device payment methods, often without requiring additional external hardware.

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Wikipedia