RNG stands for
Random Number Generator. The RNG is a special function in the
computer program running the slot machine that generates a
series of numbers. You can make your own simple RNG by tossing
a pair of dice repeatedly and noting the sum of the dice on
each throw. In the slot machine, the RNG is a set of
mathematical functions.
The slot machine uses the numbers from
the RNG to determine which symbols to land on the payline. For
example, the number from the RNG might be 1,283,345, which
might correspond to Megabucks-Megabucks-Blank. Better luck next
time!
Best of luck in and out of the casinos,
John