The RNG
Modern slot machines are computerized. So the odds are whatever they are programmed to be. In modern slot machines, the reels and lever are present for historical and entertainment reasons only. A Random Number Generator determines the positions of the reels. The machine's software contains it.
Random numbers are constantly generated by the RNG at an extremely high rate. The most recent random number is used to determine the result when the Play button is pressed. The result varies depending on exactly when the game is played. The result changes every fraction of a second.
It was noticed that the RNG does not actually generate random numbers. It turned out that The number sequence is repeated time after time. The cause of it is in poor programming. Pseudo RNGs with very long periods are relatively easy to build. No computer can 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. However, this is impossible for most machines, because the RNG picks numbers even when the machine is not being played. So the player cannot tell where in the sequence they are.

Payout Percentage
The percentage of winnings paid out of the money that is wagered by players is 82–98 per cent. The term theoretical payout percentage is used to denote it. The minimum theoretical payout percentage is controlled by 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 main criterion for selecting the winning patterns on slot machines is that they should yield a certain fraction of the money played to the house. As for the rest of the money it goes to the players.
At the factory when the software is written a slot machine's theoretical payout percentage is set. Changing the payout percentage after a slot machine has been placed on the gaming floor requires a physical swap of the software. As it is a time-consuming process it is done infrequently. 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.
The Nevada Gaming Commission is working now with Las Vegas casinos on technology that would allow the casino's slot manager to change the game, the odds, and the payouts remotely. The change cannot be done instantaneously, but only after the selected machine has been idle for at least four minutes. 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 after the change is made.

Machines That Are Linked
Offering of a particularly large prize, or jackpot becomes possible when a group of machines is linked in a special way. A small amount is contributed by each machine in the group to this progressive jackpot which is given to a player who gets a specific combination of symbols. The amount of the progressive jackpot is far higher than any single slot machine's.
Sometimes multiple machines form multiple casinos. In these cases the manufacturer owning these machines is responsible for paying the jackpot.

Near-miss Programming
The reel display of modern slot machines is controlled by computer software. It is possible to make the slot machine frequently display combinations that are close to winning combinations.
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. However, the combinations appearing above and below the pay line 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. The symbols that appear around the winning line in video slots are 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. So long as the near-miss above or below the pay line was not specially programmed it was recognized legal. 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. Manufacturer's practices are audited by regulators with the help of stop motion cameras.

Slot Machines Fraud
Mechanical slot machines and their coin acceptors were sometimes susceptible to 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. One of the recent attempts at defrauding slot machines is directing microwaves toward it to disrupt its proper functioning.

There are a lot of myths and superstitions about slots.
You can spot a winning slot machine.
The only way one can say that theslot machine is a winning one is only to catch this moment, when the machine pays out. 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.
In order to change how a slot willpay out is by changing the computer chip. No casino can just flip a switch.
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.
Again false. It makes no difference, as the computer only uses these as mechanisms to start the game. Only the computer determines a win or a loss and it has already determined if you are a winner or loser even before the first reel stops spinning.
Playing with hot coins improves your chances.
It is false. Nothing can affect the outcome, the machine doesn’t care and doesn’t know whether your coins are cold or hot.
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.

It seems that every type of activity has its own rules of etiquette, and playing the slots is no exception. 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. To decide whether to deal or not to deal with this slot machine is of great importance. As a gambler you are sure to have faced such a problem: you want to go to the bar or to the restroom, but still want to keep this slot. How can other understand that your 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. Instead of the coin cup you can leave something of your belongings. For example, a jacket or a coat. But it will work in casinos where the cashless system is used. In your turn if you see somebody’s belongings or a coin cup never sit to this slot machine. You can sit to any other slot machine. Sometimes you can find in the slot machine a card left by the previous player. If it happens to you, put the card on the top of the slot machine. The player will come back and find it easily. Nowadays most casinos allow smoking while playing. Of course, others will hardly like it, so try to make as few inconveniences as possible. Tipping the attendant that brings you the winning is one more etiquette rule. There are a lot of questions about the sum of a tip. In the case of a jackpot tip him with 0,5% of your jackpot.

The USA
In the United States the availability of slot machines is regulated by governments. Many states have established gaming control boards for regulating the possession and use of slot machines. There is only one state that has no significant restrictions against slot machines - Nevada. Slot machines are allowed only in hotel casinos operated in Atlantic City in New Jersey. Several states allow slot machines only on licensed riverboats or permanently-anchored barges. Only three horse tracks are allowed to have slot machines in Delaware. State lottery commission exists for their regulating.

Casinos: Native American
Native American casinos located in reservations are not permitted to have slot machines. But when the tribe first reaches a pact with the state in which it is located it is permitted. The state is entitled to receive a fraction of the gross revenue from slot machines by the pact.

Classes Of Slots
Slot machines aren't governed by any federal law. There are different classifications of them. Some states have restrictions on the type of slot machines that can be used in a casino or other gaming area. "Class III" (or "traditional") slot machines operate independently from a centralized computer system. A player's chance of winning any payout is the same with every play. Class III slots are most often seen in Nevada or Atlantic City. The term "Vegas-style slots" is iften used to denote them.
A centralized computer system is connected to "Class II" slot machines ("video lottery terminals" or "VLTs"). The outcome of each wager is determined by it. The chance of winning a series of limited prizes is equal for each machine. There is a fee for each Class III game that the casino has to pay to the state. The state doesn't regulate Class II games so tightly.

Characteristics Of Class II Games
The player is playing against other players. There is a common prize for which they are competing. There is always someone who wins. The game stops when the winner appears. There is a certain number of wins and losses in a given set of wins. The combimation that has already occurred cannot occur again until a new batch is initiated. The games depend on one another. The player is an active participant of the game. All players play from the same set of numbers as the numbers are announced.

Class III Game Characteristics
The opponents are the player and the house. Each game is independent of previous games. The outcome of any game is unpredictable.

Slot Clubs
In American casinos there are "slot clubs" the membership of wich is free. Complimentary food, drinks, hotel rooms, or merchandise are called comps and this is the way a small fraction of the amount of money that is bet is returned to the players. The requirement of such clubs is the usage of cards for the slot machines. The differences in the maximum theoretical returns can be significant thanks to comps or "cash back" from these clubs.

Slots In Australia
One of the most popular Australian poker machine games is Queen of the Nile. Gaming Machines is an official name for Australian slot machines. Australian-style gaming machines have video displays for stimulating physical reels. There are usually five of them. The use of gaming machines in Australia is regulated by the laws.
Not only casinos but also pubs and clubs in some states have Gaming machines. The first Australian state to legalize this style of gambling was New South Wales. In 1956 they became legal in all registered clubs in the state.
Only particular forms of gaming machine are permitted to be used in Western Australia.

United Kingdom
Fruit machines, one-armed bandits and AWP are the names for slot machines in Britain. Fruit machines can be met in pubs, clubs, arcades, and some take-away food shops. These machines commonly have 3, but can be found with 4 or 6 reels with around 16 or 24 fruit symbols printed around them. These reels should be spun. The machine pays winnings if certain combinations of fruit appear. There is similarity between these machines and slot machines seen in casinos and elsewhere around the world. But there are some extra features. The jackpots from these machines are limited. There are some features of fruit machines in the UK. There is an opportunity for a player to hold one or more reels before spinning. The chance of winning can sometimes be increased. A finite number nudges following a spin is given to a player. A single-step rotation of a reel of the player's choice is a called a nudge.
The maximum payout for an individual game depends on the type and the location of the machine. There are "club machines" in private members' clubs. They charge more per game and have higher jackpots.
These machines differ from American slot machines. The jackpot can be won in each game independently.
The AWP fruit machine is played in Europe and in countries such as the Czech Republic, Russia, and Ukraine.

Japan
Japanese slot machines are known as pachisuro. They originate from the traditional Japanese pachinko game. Slot machines have appeared recently. Pachinko parlors and the adult sections of amusement arcades, known as game centers have them.
The machines are regulated with IC chips. There are six different levels changing the odds of a "777". There are certain rules and regulations in spite of the many varieties of the machines.

Have you ever met a man who has managed to cheat slots?
Slot machines pay on a random basis, but what if you could improve the payout a little? Would you do it? Tommy Glenn Carmichael would and did.
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. Upon his release, he continued to work on the problem and to devise a better way to cheat the new slot machines. His next invention was a slider, a guitar wire. He inserted it into the machine, which released coins form 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. He fooled a manufacturer into believing he was a customer and showing him the inside of a slot machine. It was enough for Tommy. 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. Other gamblers liked his invention and he had a lot of customers, which allowed him to earn up to ,000 a day. Now he could afford the most expensive cars and several houses.
Eventually, all good things come to an end. Tommy was caught using his invention in one of the casinos. 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.