Abstract: A usage control system for copiers and the like, adapted to connect to the copier through the existing accounting system connection. A check-operated device, such as a coin box or magnetic card reader, supplies the copier with a signal to initiate operation. When the operation has progressed, the copier supplies a signal intended to increment the counter in the accounting system. After a suitable delay, permitting completion of the copy cycle, the operate signal is reset, and the copier is disabled. As an option, power to the copier may be controlled. The system requires no internal connections or modifications to the copier.