Knuckle-buster is a slang term that indicates the financial usage of manual credit card imprinted. This was a device that was used before the introduction of point-of-sale terminals, that has become hugely popular.
The term knuckle buster represents the usage of manual credit card, that was used widely and there and was physically extremely exhausting for the vendors who would injure their knuckles literally. This was before the point-of-sale terminals were introduced and this caused some serious injurious.
Despite it being known as zip-zap machines at the time, they proved to injure the vendors regularly and thus the term got stuck with it for a long time until point-of-sale terminals came along in the 1980s.
Some manual imprinters would come with a plate that would include the merchant's name, address, and other personal details, while others would not. The carbon transaction forms were purchased by other merchants who had their company information pre-printed on them.
There were many technical benefits that were offered by the point-of-sale terminals that was initially launched in 1979. They offered faster and smoother transaction both for the consumer and the shopkeeper with no injuries to the knuckles.
Apart from that when it came to the taxes and billing system, it was much easier to verify the transactions of the credit card account holder. This made the shopping experience smoother and enjoyable.
Despite this, knuckle-busters continue to be an attractive backup option for companies who want to continue operating transactions even if power or computer networks are down for an extended period. Aside from that, they are nevertheless helpful for businesses that need a portable means of documenting transactions (for example, fair vendors).
Manual input of credit card transactions is more time-consuming for retailers, and each entry increases the chance of the transaction not being validated. Furthermore, credit card companies are increasingly issuing cards that are not embossed with consumer data, rendering the knuckle-buster completely ineffective in collecting consumer data, even when performing a manual transaction with a credit card.