Bill validator (validator, bill acceptor) – unit , designed for the reception of paper money, usually used in devicesand systems, self-service population (shopping and gaming machines, payment terminals). With the help ofsystems of sensors, bill acceptor determines the denomination of bills and checks its authenticity, using the comparison of the optical and magnetic characteristics of bills with the benchmark images stored in the built-in flashmemory. Accepted bills are stored in the stacker (metal box, safe) or in a special bag.