Fallback method: card imprinter
If your card machine unexpectedly stops working, you can default to the old-fashioned credit card imprinting machine. This device produces a carbon copy of the embossed card details onto paper slips. These slips may be sent to the bank for verification, or used for manually processing the information later in a virtual terminal.
It works this way: The card imprinter has a sliding mechanism that applies pressure to carbon paper copies placed over the embossed card number and details of the customer’s payment card (i.e. this doesn’t work with cards that are not embossed). You may add extra details in handwriting, for instance the CCV code at the back of the card, transaction total, signature (yours and customer’s) – enough information to have the payment verified later. You can also ask the customer for ID to match the name on the card.
The credit card imprinter was a common sight pre-1990s, but shops now only use it in special circumstances, e.g. if a card terminal doesn’t work, the internet is down or a customer’s card has to be entered manually later.