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4 February 2000

Dear John,

I'm confused about how slot machines decide the outcome of a spin. One expert says there's a laser in the machine that wiggles over a chip and reads pits in the chip. But I read in Strictly Slots that there's a Random Number Generator in the machine, and it chooses the outcome when the first coin is played or I press the Spin button.

Who's right?

Thanks,
Otis

Dear Otis,

Strictly Slots is correct. A mathematical function that is part of the control program run by the computer in the slot machine determines the outcome of the spin. This function is called the Random Number Generator (RNG).

Different machines poll the RNG to decide the outcome of a spin at different times. Some machines do it when you drop the first coin in the slot or press the Bet One button. Others wait until you press the Spin Button or the Bet Max button. Some machines poll the RNG once to find the stopping positions of all three reels and the outcome of any bonus event--regardless of whether or not you'll play the bonus event this spin. Others make repeated polls of the RNG, once for each reel, and then again if it needs to for the bonus event.

The bottom line for slot players is this: It doesn't matter how exactly the machine uses the RNG. The outcomes appear to be chosen at random to us.

All the best in and out of the casinos!
John

Send your slot and video poker questions to John Robison, Slot Expert, at slotexpert@home.com.

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John Robison

John Robison is an expert on slot machines and how to play them. John is a slot and video poker columnist and has written for many of gaming’s leading publications. He holds a master's degree in computer science from the prestigious Stevens Institute of Technology.

You may hear John give his slot and video poker tips live on The Good Times Show, hosted by Rudi Schiffer and Mike Schiffer, which is broadcast from Memphis on KXIQ 1180AM Friday afternoon from from 2PM to 5PM Central Time. John is on the show from 4:30 to 5. You can listen to archives of the show on the web anytime.

Books by John Robison:

The Slot Expert's Guide to Playing Slots
John Robison
John Robison is an expert on slot machines and how to play them. John is a slot and video poker columnist and has written for many of gaming’s leading publications. He holds a master's degree in computer science from the prestigious Stevens Institute of Technology.

You may hear John give his slot and video poker tips live on The Good Times Show, hosted by Rudi Schiffer and Mike Schiffer, which is broadcast from Memphis on KXIQ 1180AM Friday afternoon from from 2PM to 5PM Central Time. John is on the show from 4:30 to 5. You can listen to archives of the show on the web anytime.

Books by John Robison:

The Slot Expert's Guide to Playing Slots