"It was a 2 1/2" x 1 1/4" rectangle of sheet metal, similar to a military dog tag, that was embossed with the customer's name, city and state (no address). It held a small paper card for a signature. It was laid in the imprinter first, then a charge slip on top of it, onto which an inked ribbon was pressed. Charga-Plate was a trademark of Farrington Manufacturing Co. Charga-Plates were issued by large-scale merchants to their regular customers, much like department store credit cards of today. In some cases, the plates were kept in the issuing store rather than held by customers. When an authorized user made a purchase, a clerk retrieved the plate from the store's files and then processed the purchase. Charga-Plates speeded back-office bookkeeping that was done manually in paper ledgers in each store, before computers" (Wikipedia article on Credit card, accessed 12-26-2008).
Filed under: Accounting / Business Machines