<p>A cash validation system is used with a point of sale system to provide a self service check out system. The cash validation system comprises a bill acceptor for receiving paper currency. A coin changer receives and dispenses coins. A control unit is operatively coupled to the bill acceptor and the coin changer for monitoring and commanding operation of the bill acceptor and the coin changer. An interface is operatively coupled between the control unit and the point of sale system for communicating information on received paper currency and coins to the point of sale system and receiving requests from the point of sale system to dispense change and response to the requests commanding operation of the coin changer.</p>
