Changing the payout percentage after a slot machine has been placed on the gaming floor requires a physical swap of the software or firmware, which is usually stored on an eprom but may be loaded onto non-volatile random access memory( nvram ) or even. The prototype was mounted in a full size show-ready slot machine cabinet. Because the typical machine stopped the reels automatically in less than 10 seconds, weights were added to the mechanical timers to prolong the automatic stopping of the reels. The psychology of the machine design is quickly revealed. Another obsolete method of defeating slot machines was to use a light source to confuse the optical sensor used to count coins during payout. Breen, Robert B (2004). By way of comparison, the US State of Nevada which legalised gaming including slots several decades before NSW, had 190,135 slots operating. Regulatory authority over class I gaming is vested exclusively in tribal governments and is not subject to igra's requirements. Typically, a pact entitles the state to receive a fraction of the gross revenue from slot machines.