Random Number Generator
There are many modern computerized slot machines. The odds are programmed. In modern slot machines, the reels and lever are present for historical and entertainment reasons only. The positions of the reels are chosen by a Random Number Generator. The machine's software includes a Random Number Generator.
The RNG generates random numbers at an extremely high rate. When a player presses the Play button the most recent random number determines the result. The result varies depending on exactly when the game is played. The result changes every fraction of a second.
Some professional gamblers observe that the RNG does not actually generate random numbers. It turned out that The number sequence is repeated time after time. Poor programming determines such behavior. It is relatively easy to build pseudo RNGs with very long periods. There is no computer that is able to complete a single period in the expected lifetime of the universe. Ronald Dale Harris, a former slot machine programmer, was the only one who had access to the pseudo RNG code and seed values. Equations for specific gambling games like Keno were discovered by him. Thanks to them the fact that the next set of selected numbers would be based on the previous games became known. But the RNG picks numbers even when the machine is not being played. So the player cannot see the secquence.

Percentage Of The Payout
Slot machines usually pay out as winnings 82–98 per cent of the money that is wagered by players. This is known as the theoretical payout percentage. The minimum theoretical payout percentage varies among jurisdictions. Law or regulation typically establish it. Nearly each casino has its own winning pattern. It contains the information about the amounts they pay and the frequencies of these pay-outs. The winning patterns on slot machines are carefully selected to yield a certain fraction of the money played to the house. As for the rest of the money it goes to the players.
When a slot machine's software is written its theoretical payout percentage is also set. Changing the payout percentage after a slot machine has been placed on the gaming floor requires a physical swap of the software. Being a time-consuming process it is done not very often. Certain jurisdictions presuppose the EPROM to have a tamper-evident seal. To change it Gaming Control Board officials should be present. Other jurisdictions randomly audit slot machines to ensure that they contain only approved software.
Thanks to the newly developed technology the game, the odds, and the payouts would be able to be changed by the casino's slot manager remotely. The change cannot be done instantaneously, but only after the selected machine has been idle for at least four minutes. After the change is made, the machine must be locked to new players for four minutes and display an on-screen message informing potential players that a change is being made.

Machines Linking
Offering of a particularly large prize, or jackpot becomes possible when a group of machines is linked in a special way. If a player gets a specific combination of symbols the progressive jackpot from this group of machines is given to him. A single slot machine's jackpot is considerably less than the progressive jackpot.
Multiple machines can be sometimes linked across multiple casinos. The machines are then owned by the manufacturer, who is responsible for paying the jackpot.

Near-miss Programming
The reel display of modern slot machines is under computer software's control. Combinations that are close to winning combinations can be displayed on the slot machine intentionally.
The term near-miss programming is used to denote this practice.
There is a related phenomenon which is also called near-miss. The chance of a winning combination appearing on a pay line is controlled by the winning percentages programmed into the slot machine. The combinations above and below the payline are all roughly equally randomly distributed. This means it is much more likely that a winning combination will appear above or below a pay line than on the pay line. This phenomenon only occurs where abbreviated physical reels are used to display a win pattern based upon the RNG. Video slot machines have virtual reels and the symbols that appear around the winning line are usually an accurate depiction of how the reels were mathematically modeled.
The issue of a near-miss above or below the pay line was also the subject of the Nevada Gaming Commission investigation. They ruled that this was legal, so long as the near-miss above or below the pay line was not specially programmed. That means that the possibility of near-miss occurrence should be equal to the possibility of any other combination. The machine cannot be specially programmed to show winning combinations more frequently than other combinations above or below the pay line.
In Australia the usage of near-miss programming, where a near miss is inaccurately displayed is also illegal. To audit manufacturer's practices regulators use stop motion cameras.

Fraud
Mechanical slot machines and their coin acceptors were sometimes considered to be cheating devices and other scams.
Modern slot machines are controlled by EPROM computer chips and coin acceptors have become obsolete in favor of bill acceptors. Different advanced anti-cheating and anti-counterfeiting measures have been taken to make it difficult to defraud these machines. Recent attempts at defrauding slot machines involve manipulating the EPROM, such as by directing microwaves toward it to disrupt its proper functioning.

Here is the list of the most amusing myths concerning slots.
You can spot a winning slot machine.
The only way you'll spot a winning slot machine is when the bells are ringing and the money is dropping. Slot machines use random numbergenerator and that's exactly that. Random.
Casinos place loose slots near the cashier, aisle ways, etc.
In reality it is not to casino’s advantage to place loose slots at one and the same place, because in this case gamblers would play only these slots. The slots are mixed and nobody can say for sure whether this slot is a loose one or not.
Count the number of symbols on the reels to determine your odds.
It is a rude mistake. RNG decides when the machine will stop and there are thousands of combination available on a 3 reel slot machine.
Casinos can tighten or loosen slot machines from the back office.
It is not as simple as that. The casino can’t just change the chip of the slot machine. It is illegal and it has to be permitted by the commission.
A slot machine that has not been paying is due to hit.
It is not so. With every game the chances of winning are the same.
Pulling the slot machine handle produces more wins than pressing the spin button and visa versa.
It is also a mistake. These things are only mechanisms for beginning the game. The machine knows whether you win or lose before the symbols begin to stop.
Playing with hot coins improves your chances.
Once again, the computer determines a win or loss and the temperature of the machine or moneyirrelevant. Although it's funny that people still burn their fingers with lighters believing this works.
Casinos set slot machines to payback more on the weekends.
One more rude mistake. The chances and odds are always the same. It doesn’t matter when you play.

Like any casino game slots have their own rules of etiquette. Even though playing the slots is primarily a solo activity, there are definite do's and don'ts when it comes to playing the slots. First of all decide whether to deal or not to deal with this very slot machine. Imagine you leave the slot and go to the bar or to the restroom and you want to come back in a few minute and continue playing. How can you let other people know that the slot machine is in play? If you hang a coin cup over the handle of the slot machine it will mean that this slot is in play by you. Placing the coin cup on the seat has the same meaning. In casinos that use a cashless system, a personal item such as a jacket can be placed on the seat instead. In your turn you should respect other players and never sit to a slot that is in play. If you find a card left by the previous player the second etiquette rule has to be applied. It happens very often that a player leaves his card and walks away. If you face a situation like this you have to put the card on the top of the slot machine where it can be easily seen and found. Nowadays most casinos allow smoking while playing. Of course, others will hardly like it, so try to make as few inconveniences as possible. Tipping is another difficult issue for many slot players, and many people are unsure how much to tip the attendant that brings the winnings. For jackpots that require a hand payout, the customary tip is one half of one percent of the jackpot.

You can be sure that slot machines are designed to be honest. What you can really doubt is the honesty of some manufactures.
In the old days, slot machines worked mechanically, with independent wheels spinning until they each stopped randomly. Today’s slot machines are light years away from those lumbering machines of old. These machines contain computer chips that are programmed to select numbers randomly. The selected number determines the symbol which then comes out. The computer code that generates the random numbers is responsible for whether the machine is “loose” or “tight,” so gaming inspectors look at the machine’s code to make sure that a slot machine doesn’t cheat. That is, inspectors make sure that the machine pays off at the legal rate or better.
Because slot machines don’t pay off with every spin, it’s difficult for customers to tell whether a slot machine’s chip has been programmed to pay off less often than is legally required. Before the machines are installed in casinos they are examined by inspectors. But you must understand that inspectors can’t examine every machine. They examine the brands. Once inspectors approve a brand of machine, the manufacturers can make changes to individual machines as long as the changes fall within the legal bounds. Using their right to produce slot machines they insert different chips, which makes the machine pay less.
For example, the Nevada Gaming Commission caught American Coin using chips that did not allow poker royal flushes. Or a chip that shows near misses of a jackpot. The player would never hit a jackpot but keep on playing maximum bets. If you think that you have come across such a machine you have a right to complain. In the case if the complaint the inspectors will visir the casino and check whether the machines have a legal chip. Manufacturers that cheat are fined or they can lose their license.

Meet the man who beat the slots.
It is impossible to cheat the slot machine, but to improve the payout is possible. It was proved by a gambler whose name was Tommy Glenn Carmichael.
A 53-years Tommy all his life tried to invent some kind of devices to cheat the slot machine. His first device was a kind of a top-button joint. By the way, for this device he was sent to prison. Then he was released, but continued to work at inventing devices for cheating a slot. The principle of his next invention was following: he inserted a guitar wire in the slot machine and it made the coins release from the hopper.
Later the slot machines were not any longer mechanical, they were computerized and as a result there appeared a need for a new device. In some way he managed to fool the manufacture who showed him the inner construction of a slot machine. From that experience, he learned what he needed to know to beat it. Carmichael invented what he called a “light wand. ” The wand, built with a camera battery and a bright miniature light, was used to shine into the slot machine and blind a sensor, causing the hopper to pay out coins. He sold these wands and could earn up to ,000 a day. With all this money he bought expensive cars, houses and what not.
But as known good things can’t last forever. For Carmichael, they ended in front of a slot machine at Circus, where he was caught with the light wand when he tried to run from security. While charges from that incident were later dropped, he was caught under similar circumstances in Laughlin and later Atlantic City. By this time, authorities had tapped his phone and recorded conversations with other cheats who used his device. He served three years’ probation and lost both homes. He has been banned from entering any casino.