A cash register is a device for calculating and recording sales transactions. A cash drawer for storing cash is attached and the register usually prints a receipt. Cash registers were first invented in order to deter employee theft and embezzlement. It is theorized that odd prices such as 49 and 99 cents came about so that it was almost guaranteed the cashier would have to provide a penny in change and therefore announce the sale. Most of the time the drawer could only be opened after a sale, except when using special keys which only senior employees and owners have.
James Ritty was the inventor of the cash register. He owned a saloon in Dayton, Ohio and wanted to stop employees from pilfering his profits. The register he invented was the Ritty Model I in 1879 after seeing a tool that counted the revolutions of the propeller on a steamship. These first registers were entirely mechanical and without receipts. They were basically simple adding machines that required every transaction to be ring up and when the total key was pressed a bell would sound and the drawer would open.
After getting his patent Ritty was overwhelmed with running two businesses so he sold his interest in the cash registers to Jacob H. Eckert of Cincinnati. Eckert sold the company to John H. Patterson who changed the company to the National Cash Register Company and added the roll of paper which later became the receipt.
Charles F. Kettering was the first to design a register with an electric motor. Many registers have a no sale key that opens the drawer, and records it in the register log. Other registers require a key to open the till. More and more registers are being replaced with general purpose computers with POS software. The machines scan barcodes to get the price, calculate reductions and update inventory.
Today, many registers are individual computers running on DOS, Windows, or unix and many have touch screens. Many supermarkets have introduced self-checkout machines where the customer scans the barcode of the item. The machine weighs the purchased item and halts the transaction if the weight is different than the scanned item should be. Payment can be made through debit, credit, and cash. Store employees have to authorize age-restricted purchases such as alcohol, solvents, and knives.