The random number generator is responsible for every result after a player pushes the button. A computer programmer at the factory programs the RNG or assigns it certain combinations for every situation that may occur on the reels. The RNG reacts immediately after the first coin is dropped into the slot machine.
Modern gaming machines use computer technology to operate their functions. Slot machine outcomes are determined unsing a Random Number Generator (RNG) which is a mathematically-based program that selects groups of numbers to determine which symbols are selected to produce a winning or losing outcome.