Protection circuit for electronic gaming machines - records attempts to gain access and inhibit further use until coded electronic key is used

摘要

If a break-in is attempted, one or more microswitches close, energising a relay via a power supply. The relay contacts feed a non-volatile RAM powered by an internal battery. The RAM is connected via an 8-bit bus to the machine's central processor and to EPROM and latch circuits. - The latch circuit inhibits any further use of the machine until a PAL memory electronic key is plugged into a connector. If the data supplied by the key are identical to those stored in the EPROM and the circuits have not been tampered with, the system is reset to normal operation.