How Slot Machine Works In Casino

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In the not-too-distant past, slot-machine players were the second-class citizens of casino customers. Jackpots were small, payout percentages were horrendous, and slot players just weren't eligible for the kind of complimentary bonuses -- free rooms, shows, meals -- commonly given to table players. But in the last few decades the face of the casino industry has changed. Nowadays more than 70 percent of casino revenues comes from slot machines, and in many jurisdictions, that figure tops 80 percent.

Slot machines are designed to be tamper proof to both the players and the casino. Slot machines are designed to be tamper proof to both the players and the casino.

About 80 percent of first-time visitors to casinos head for the slots. It's easy -- just drop coins into the slot and push the button or pull the handle. Newcomers can find the personal interaction with dealers or other players at the tables intimidating -- slot players avoid that. And besides, the biggest, most lifestyle-changing jackpots in the casino are offered on the slots.

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The following article will tell you everything you need to know about slots, from the basics to various strategies. We'll start at square one, with a primer on how playing slot machines works.

How to Play

The most popular slots are penny and nickel video games along with quarter and dollar reel-spinning games, though there are video games in 2-cent, 10-cent, quarter, and dollar denominations and reel spinners up to $100. Most reel spinners take up to two or three coins at a time while video slots can take 45, 90, and even 500 credits at a time.

Nearly all slot machines are fitted with currency acceptors -- slide a bill into the slot, and the equivalent amount of credits is displayed on a meter. On reel-spinning slots, push a button marked 'play one credit' until you've reached the number of coins you wish to play. Then hit the 'spin reels' button, or pull the handle on those few slots that still have handles, or hit a button marked 'play max credits,' which will play the maximum coins allowed on that machine.

How Slot Machines Work In Casinos

On video slots, push one button for the number of paylines you want to activate, and a second button for the number of credits wagered per line. One common configuration has nine paylines on which you can bet 1 to 5 credits. Video slots are also available with 5, 15, 20, 25, even 50 paylines, accepting up to 25 coins per line.

Many reel-spinning machines have a single payout line painted across the center of the glass in front of the reels. Others have three payout lines, even five payout lines, each corresponding to a coin played. The symbols that stop on a payout line determine whether a player wins. A common set of symbols might be cherries, bars, double bars (two bars stacked atop one another), triple bars, and sevens.

A single cherry on the payout line, for example, might pay back two coins; the player might get 10 coins for three of any bars (a mixture of bars, double bars, and triple bars), 30 for three single bars, 60 for three double bars, 120 for three triple bars, and the jackpot for three sevens. However, many of the stops on each reel will be blanks, and a combination that includes blanks pays nothing. Likewise, a seven is not any bar, so a combination such as bar-seven-double bar pays nothing.

Video slots typically have representations of five reels spinning on a video screen. Paylines not only run straight across the reels but also run in V's, upside down V's, and zigs and zags across the screen. Nearly all have at least five paylines, and most have more -- up to 50 lines by the mid-2000s.

In addition, video slots usually feature bonus rounds and 'scatter pays.' Designated symbols trigger a scatter pay if two, three, or more of them appear on the screen, even if they're not on the same payline.

Similarly, special symbols will trigger a bonus event. The bonus may take the form of a number of free spins, or the player may be presented with a 'second screen' bonus. An example of a second screen bonus comes in the long-popular WMS Gaming Slot 'Jackpot Party.' If three Party noisemakers appear on the video reels, the reels are replaced on the screen with a grid of packages in gift wrapping. The player touches the screen to open a package and collects a bonus payout. He or she may keep touching packages for more bonuses until one package finally reveals a 'pooper,' which ends the round. The popularity of such bonus rounds is why video slots have become the fastest growing casino game of the last decade.

When you hit a winning combination, winnings will be added to the credit meter. If you wish to collect the coins showing on the meter, hit the button marked 'Cash Out,' and on most machines, a bar-coded ticket will be printed out that can be redeemed for cash. In a few older machines, coins still drop into a tray.

Etiquette

Many slot players pump money into two or more adjacent machines at a time, but if the casino is crowded and others are having difficulty finding places to play, limit yourself to one machine. As a practical matter, even in a light crowd, it's wise not to play more machines than you can watch over easily. Play too many and you could find yourself in the situation faced by the woman who was working up and down a row of six slots. She was dropping coins into machine number six while number one, on the aisle, was paying a jackpot. There was nothing she could do as a passerby scooped a handful of coins out of the first tray.

Sometimes players taking a break for the rest room will tip a chair against the machine, leave a coat on the chair, or leave some other sign that they'll be back. Take heed of these signs. A nasty confrontation could follow if you play a machine that has already been thus staked out.

Payouts

Payout percentages have risen since the casinos figured out it's more profitable to hold 5 percent of a dollar than 8 percent of a quarter or 10 percent of a nickel. In most of the country, slot players can figure on about a 93 percent payout percentage, though payouts in Nevada run higher. Las Vegas casinos usually offer the highest average payouts of all -- better than 95 percent. Keep in mind that these are long-term averages that will hold up over a sample of 100,000 to 300,000 pulls.

In the short term, anything can happen. It's not unusual to go 20 or 50 or more pulls without a single payout on a reel-spinning slot, though payouts are more frequent on video slots. Nor is it unusual for a machine to pay back 150 percent or more for several dozen pulls. But in the long run, the programmed percentages will hold up.

The change in slots has come in the computer age, with the development of the microprocessor. Earlier slot machines were mechanical, and if you knew the number of stops -- symbols or blank spaces that could stop on the payout line--on each reel, you could calculate the odds on hitting the top jackpot. If a machine had three reels, each with ten stops, and one symbol on each reel was for the jackpot, then three jackpot symbols would line up, on the average, once every 10310310 pulls, or 1,000 pulls.

On those machines, the big payoffs were $50 or $100--nothing like the big numbers slot players expect today. On systems that electronically link machines in several casinos, progressive jackpots reach millions of dollars.

The microprocessors driving today's machines are programmed with random-number generators that govern winning combinations. It no longer matters how many stops are on each reel. If we fitted that old three-reel, ten-stop machine with a microprocessor, we could put ten jackpot symbols on the first reel, ten on the second, and nine on the third, and still program the random-number generator so that three jackpot symbols lined up only once every 1,000 times, or 10,000 times. And on video slots, reel strips can be programmed to be as long as needed to make the odds of the game hit at a desired percentage. They are not constrained by a physical reel.

Each possible combination is assigned a number, or numbers. When the random-number generator receives a signal -- anything from a coin being dropped in to the handle being pulled -- it sets a number, and the reels stop on the corresponding combination.

Between signals, the random-number generator operates continuously, running through dozens of numbers per second. This has two practical effects for slot players. First, if you leave a machine, then see someone else hit a jackpot shortly thereafter, don't fret. To hit the same jackpot, you would have needed the same split-second timing as the winner. The odds are overwhelming that if you had stayed at the machine, you would not have hit the same combination.

Second, because the combinations are random, or as close to random as is possible to set the program, the odds of hitting any particular combination are the same on every pull. If a machine is programmed to pay out its top jackpot, on the average, once every 10,000 pulls, your chances of hitting it are one in 10,000 on any given pull. If you've been standing there for days and have played 10,000 times, the odds on the next pull will still be one in 10,000. Those odds are long-term averages. In the short term, the machine could go 100,000 pulls without letting loose of the big one, or it could pay it out twice in a row.

So, is there a way to ensure that you hit it big on a slot machine? Not really, but despite the overriding elements of chance, there are some strategies you can employ. We'll cover these in the next section.

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Slots are the easiest games in the casino to play -- spin the reels and take your chances. Players have no control over what combinations will show up or when a jackpot will hit. There is no way to tell when a machine will be hot or cold. Still, there are some pitfalls. It's important to read the glass and learn what type of machine it is. The three major types of reel-spinning slots are the multiplier, the buy-a-pay, and the progressive.

The multiplier. On a multiplier, payoffs are proportionate for each coin played--except, usually, for the top jackpot. If the machine accepts up to three coins at a time, and if you play one coin, three bars pay back ten. Three bars will pay back 20 for two coins and 30 for three coins. However, three sevens might pay 500 for one coin and 1,000 for two, but jump to 10,000 when all three coins are played. Read the glass to find out if that's the case before playing less than the maximum coins on this type of machine.

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The buy-a-pay. Never play less than the maximum on a buy-a-pay, on which each coin 'buys' a set of symbols or a payout line. The first coin in might allow the player to win only on cherry combination, while the second coin activates the bar payouts, and the third coin activates the sevens. Woe is the player who hits three jackpot symbols on a buy-a-pay with only one coin played--the player gets nothing back. A variation is the machine with multiple payout lines, each activated by a separate coin. All symbols are active with each coin, but if a winning combination lines up on the third-coin payout line with only one or two coins played, the payoff is zero.

Slot

The progressive. You also have no reason to play less than maximum coins on a progressive machine. A player who eventually lines up the jackpot symbols gets a percentage of each coin played. The first progressive machines were self-contained--the jackpot was determined by how much that particular machine had been played since the last big hit. Today most progressives are linked electronically to other machines, with all coins played in the linked machines adding to a common jackpot.

These jackpots can be enormous -- the record is $39,710,826.26, a $1 progressive at a Las Vegas casino. The tradeoff is that frequency and size of other payouts are usually smaller. And you can't win the big jackpot without playing maximum coins.

If you must play fewer than maximum coins, look for a multiplier in which the final-coin jump in the top jackpot is fairly small. Better yet, choose a machine that allows you to stay within your budget while playing maximum coins. If your budget won't allow you to play maximum coins on a $1 machine, move to a quarter machine. If you're not comfortable playing three quarters at a time, move to a two-quarter machine. If you can't play two quarters at a time, play a nickel machine.

With so many paylines and the possibility of betting multiple coins per line, video slots are different. Some penny slots with 20 paylines take up to 25 coins per line. That's a $5 maximum bet -- a pretty penny indeed! Most players bet less than the max on video slots but are sure to cover all the paylines, even if betting only one coin per line. You want to be sure to be eligible for the bonus rounds that give video slots most of their fun. Some progressive jackpots require max coins bets, and some don't. If a max-coins bet is required to be eligible for the jackpot and you're not prepared to roll that high, find a different machine.

Money Management

Managing your money wisely is the most important part of playing any casino game, and also the most difficult part of playing the slots. Even on quarter machines, the amount of money involved runs up quickly. A dedicated slot player on a machine that plays off credits can easily get in 600 pulls an hour. At two quarters at a time, that means wagering $300 per hour -- the same amount a $5 blackjack player risks at an average table speed of 60 hands per hour.

Most of that money is recycled from smaller payouts--at a casino returning 93 percent on quarter slots, the expected average loss for $300 in play is $21. Still, you will come out ahead more often if you pocket some of those smaller payouts and don't continually put everything you get back into the machine.

One method for managing money is to divide your slot bankroll for the day into smaller-session bankrolls. If, for example, you've taken $100 on a two-and-a-half-hour riverboat cruise, allot $20 for each half-hour. Select a quarter machine -- dollar machines could devastate a $100 bankroll in minutes -- and play the $20 through once. If you've received more than $20 in payouts, pocket the excess and play with the original $20. At the end of one half-hour, pocket whatever is left and start a new session with the next $20.

If at any point the original $20 for that session is depleted, that session is over. Finish that half-hour with a walk, or a snack, or a drink until it is time for a new session. Do not dip back into money you've already pocketed.

That may seem rigid, but players who do not use a money management technique all too frequently keep pumping money into the machine until they've lost their entire bankroll. The percentages guarantee that the casino will be the winner in the long run, but lock up a portion of the money as you go along, and you'll walk out of the casino with cash on hand more frequently.

That is changing in new server-based slots that have started to appear in casinos. Operators will be able to change payback percentages at the click of a mouse, but they still must have regulatory approval to do so.

There is a lot more to slot machines than meets the eye. But if you learn the ins and outs of playing them, you can use some strategies that just might help you hit the jackpot.

©Publications International, Ltd.

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This is what is known about casino slot machines:

The RNG (Random Number Generator)

The Random Number Generator (RNG) is the brains of the slot machine. While most player know that there is a computer chip picking the numbers, they do not fully understand how it works and this can lead to some of the many myths and misconceptions about a slot machine. One of the most common myths is that a machine has a cycle that can let a player know when it is due to hit. – This is completely false and heres why. Inside the slot machine is a microprocessor similar to the one in your home computer. Instead of running Word or Excel, it runs a special program known as the RNG. This generates numbers to correspond to the symbols on the reel of the slot machine and decides the outcome of the game cycle. You might say that the RNG is in perpetual motion. As long as there is power to the machine it is constantly selecting random numbers every millisecond. The RNG generates a value between 0 and 4 billion (approx number) which is then translated into a specific set of numbers to correspond to the symbols on the reels. The outcome of each spin is determined by the number selected by the RNG. This number is chosen with the 1st hit of the spin button or 1st deposit of a coin. The RNG uses a formula known as an algorithm which is a series of instructions for generating the numbers. The scope of this is beyond most of our mathematical knowledge but can be checked and varified for accuracy. This is done by the Casino Control Board and other testing laboratories to make sure that the program performs as it should so the player will not be cheated. While all of this may sound reasonable it still does not give the normal person any basic understanding about how the RNG works. I would like to try to explain it in a simplified manner that I think most of us can relate to. Although this is not precisely how the RNG operates it should give you a basic understanding of the principles of how the winning spins are determined and how little affect the payout percentage chip installed in a slot machine actually has. Reel type slot machines have a number of spaces and stops on each reel that contain either a symbol or blank. These are refereed to as the physical stops. Most of the old mechanical machines had reels that could hold 20 symbols while the modern slots have reels with 22 physical stops. The micro processing technology allows the newer machines to be able to accommodate a large number of “Virtual stops”. I will try to simplify things by saying this: Imagine that there are only 10 stops on each reel. With 10 stops there can be 1,000 different combinations. We get this number by multiplying the number of symbols on each reel. (10 x 10 x 10 = 1,000) The 1,000 combinations that can be attained are known as a cycle and this is the word that sometimes confuses a player into thinking that the machine has cycles of winning and losing. The odds of a three number combination being picked are one in a thousand. Theoretically if you play 1,000 spins you should see each of these number combinations once. However we all know that this is not the case. If you played a million spins you would see that the numbers would even out to be closer to the actual probability. This is similar to flipping a coin 100 times. Although the odds are 50 -50 you are unlikely to see 50 heads and 50 tails after 100 flips. This is similiar to a Daily pick 3 lottery drawing. They have three glass bowls or drums each containing ten balls numbered 0 -9. The balls are mixed up and when the top is lifted a ball pops up the tube showing you the first number. This is repeated for the second and third number to give you a three digit winning combination. To use this as an example of the operation of the slot machine, we will replace the numbers 0 -9 on the balls with slot symbols. In each bowl, we will have one ball with the jackpot symbol on it. Two balls with a Bar, three balls with a cherry and four balls which are blank. Imagine the RNG in the slot machine as the person drawing the winning combination. Here is the breakdown of the number of times out of a thousand that the winning combination made.

  • 3 Jackpot 1 (1x1x1)
  • 3 Bars 8 (2x2x2)
  • 3 Cherries 27 (3x3x3)
  • Total Wins 37
  • There are 963 losing combinations consists of:
  • 3 blanks
  • 2 blanks and a symbol.
  • 1 blank and two different symbols.
  • 3 mixed symbols.

The RNG picks these combinations of numbers thousands of times each second. Now imagine a string of blinking lights where only one bulb can be lit at a time. The electrical current is zipping from bulb to bulb down the string. When you push a button the current stops moving and the bulb in that position lights up. In this example the light represents the three digit number just picked by the RNG. If you hesitated a second before pushing the button the results would be different. This is the same as you getting up from a machine and seeing someone else sit down and hit the jackpot. The chances are astronomical that you would have hit the spin button at the exact same millisecond.

All this comes down to this:

The percentage chip payout is based over the life of the machine. The expected service of any Commercial slot machine is at least 40 million game cycles. It might pay back 500% today and 10% tomorrow. It could also pay 180% for a month straight and then 2% for a year. The average will equal the percentage chip installed in the main board. This is why when you are at a casino you can dump $1000 or more in a slot machine, take a 5 minute walk to the restroom and when you return to the machine you were playing you see someone else sitting there with a smile from ear to ear because they just won a jackpot that should belong to you, after all the money thats in the machine was yours, wasn’t it?

Slot Terms and what they mean

How Slot Machine Works In Casinos

  • PAR = Paytable and Reelstrip listing though it is widely refered to as the pay out percentage.
  • HFRQ = Hit Frequency.
  • PSR = A program summary report

From what I have learned, there are two factors that are figured into a slot machine to eventually come up with the PAR. One of those is the hit frequency and the other is the win frequency. They are mutually exclusive, Example: – If you have a high hit frequency, you will have a low win frequency, and if you have a high win frequency, you will have a low hit frequency. Hit frequency is how often the machine actually pays something, and win frequnecy is how often a big jackpot is paid. All of this shapes how volatile the machine is. The way I understand it is you can’t change those factors and not mess with the PAR, and that is part of what GLI checks with the math.

If you know what you are looking for, you can actually observe it during machine play. Compare the play on a Double Red White and Blue with a Triple Red White and Blue. While the theme sounds the same, the volatility of the machines are worlds apart. You should see lots of small payouts on the double RWB and few jackpots,and the opposite on the Triple RWB.

Hit frequency depends on how many of the possible combinations result in a win. If there are 262,144 possible combinations (a three reel, 64 positions per reel game). We may have, say 61,700 possible winning combinations (taken from a real game). For the example given, on the average about 23% of the games will result in a win of some kind.

The hold of the game may be altered by either changing the number of winning combinations, or changing how much gets paid on a certain win. The first can be done without a change in the Pay Table. The second will reflect as a change in the pay Table.

How Do Slot Machine Work

All reel games I have ever seen have many possible combinations to give a different Hold. The intention is that a different denomination for a given game be set to a given Hold. A casino can choose to have 2.5% of a dollar, or 10% of a quarter, and so on, each giving the casino about the same revenue per coin played.

Hit frequency varies more according to different games than within a given game. A higher hit frequency makes a game more exciting The pay awards are usually lower, but coming more often. A lower hit frequency game usually has higher payouts, but is hit less often. Both games can have the same Hold.

Hit frequency depends on how many of the possible combinations result in a win. If there are 262,144 possible combinations (a three reel, 64 positions per reel game). We may have, say 61,700 possible winning combinations (taken from a real game)”

So I gather that “positions” mean symbols on the reel and Is that a typical amount of combinations? (64 ^3)

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My Experience with hands on debugging of many micoporcessors and some limited programming. It seems to me with todays video processing power it could be a huge number of positions and combinations. ( I mean the reels don’t actually spin any more, its more just scrolling video data. The same goes for the RNG (Random Number Generator). To put it in layman terms, how many positions/possible combinations would a “money to burn”, “winning bid”, “jackpot party”, etc have?

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Well, Generally there are aproximately 32 positions per reel. (Ok 5 reels = a really big number.

High jackpot value = really low hit rate on the Jackpot, but lots of small wins.

Favorite Slot Machines In Casinos

Most of the hardware is pretty standard microprocessor circuits with only a few bells and whistles added. De-engineering is seldom difficult if you have done it before. Dis-assembling firmware is time consuming but an excellent learning experience. You really get a good understanding of how the game works.

List Of Casino Slot Machines

Most Stepper (reel) games have only 22 reel stops including the blanks. However, virtual numbers are assigned to the reel stops. which means that the reels can be weighted. As an example assign more virtual numbers to the blank spaces on a slot machine reel. (usually blank spaces around the symbols for the top award) This of course intices players to stay at a machine for longer periods. Im not totally sure but with the memory limitations on IGT S+ machines highest number of virtual reel stops is 64^3 however on video reel machines appear to have as many as 88 reel stops (no virtual stops for video since they are virtual reels) now the strange thing is that they can have more reel stops for some reels than others. eg:

A game with 5 reels can have 60 stops for the 5th reel 70 for the 4th 72 for the 2nd and 3rd and 88 for the 1st this would yeild 1,916,006,400 reel combos. thats a whole lot to work with. you could imagine the possibilities in tweaking either the PAR or HFRQ by fractions of a %. – All This is just my opinion, of course!