Which transaction method involves a merchant dialing a toll-free number for authorization?

The transaction method that involves a merchant dialing a toll-free number for authorization is the dial-up terminal. This method is characterized by its use of a standard telephone line to connect with the payment processor or bank to obtain transaction authorization. When a customer uses a debit or credit card, the merchant would input the card details into the dial-up terminal, which then dials a designated toll-free number to request authorization for the transaction. This process is particularly relevant for merchants that may not have access to high-speed internet connections, relying instead on traditional phone lines for transaction processing.

Understanding this technology is essential, especially in settings where reliability and ease of use are critical. Dial-up terminals can serve businesses in areas with limited connectivity options, making them a vital solution for many retailers. The other transaction methods, such as wireless terminals, IP terminals, and EMV terminals, typically rely on different technologies (like cellular networks or internet connections) that do not involve a phone-based authorization process.