Generator Of Random Numbers
Nowadays slot machines are computerized. So the odds are whatever they are programmed to be. In modern slot machines, the reels and lever exist only for historical and entertainment reasons. The positions of the reels depend on a Random Number Generator. The machine's software contains it.
The RNG generates random numbers at an extremely high rate. As soon as the Play button is pressed, the most recent random number is used to determine the result. The result varies depending on exactly when the game is played. The result would be different a fraction of a second earlier or later.
The numbers generated by the RNG seem to be not exactly random. Indeed, most RNGs will eventually repeat their number sequence. The cause of it is in poor programming. To build pseudo RNGs with very long periods is relatively easy. The computer that is able to complete a single period in the expected lifetime of the universe hasn't been invented yet. Ronald Dale Harris, a former slot machine programmer, was the only one who had access to the pseudo RNG code and seed values. It was he who discovered equations for specific gambling games like Keno. They allowed to predict that the next set of selected numbers would be based on the previous games played. But the RNG picks numbers even when the machine is not being played. So the player cannot tell where in the sequence they are.

Percentage Of The Payout
Slot machines are typically programmed to 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. It is typically established by law or regulation. A certain winning pattern is determined by every casino individually. It contains the information about the amounts they pay and the frequencies of these pay-outs. The selection of the slot machines winning patterns is chosen in such a way that it could yield a certain fraction of the money played to the house. The rest of the money is given back to the players.
A slot machine's theoretical payout percentage is set at the factory when the software is written. To change the payout percentage after a slot machine has been placed on the gaming floor a physical swap of the software is required. Being a time-consuming process it is done not very often. One can find a tamper-evident seal on the EPROM in certain jurisdictions. It can only be changed in the presence of Gaming Control Board officials. Other jurisdictions randomly audit slot machines to ensure that they contain only approved software.
The technology being developed by the Nevada Gaming Commission would allow the casino's slot manager to change the game, the odds, and the payouts remotely. Only after the selected machine has been idle for at least four minutes can the change be done. 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.

Linked Machines
Linking the machines in a special way is made to offer a particularly large prize, or jackpot. 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 paid for the progressive jackpot is usually far higher than any single slot machine could pay on its own.
In some cases multiple machines are linked across multiple casinos. In these cases the manufacturer owning these machines is responsible for paying the jackpot.

Near-miss
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.
Such showing combinations that are similar to winning combinations more frequently than would occur randomly is called near-miss programming.
There is a related phenomenon that is also sometimes 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. There are roughly equally randomly distributed combinations above and below the pay line. Only if abbreviated physical reels are used to display a win pattern based upon the RNG this can occur. In video slot machines 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 investigated by the Nevada Gaming Commission. They ruled that this was legal, so long as the near-miss above or below the pay line was not specially programmed. In other words, the near-miss must be just as likely to occur as any other combination. It is impossible to program the machine 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.

Slots Fraud
Sometimes mechanical slot machines and their coin acceptors seem to belong 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. An example of modern ways of slot machine defrauding is 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.
This is mathematically impossible, remember the RNG (random number generator) determines the stops. Thereare literally millions of combinations on a 3 reel slot machine, so there is no way of determining odds by the symbols on the reels alone.
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.
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.
Wrong again. Your odds of winning are the same no matter if it's 4:00pm Monday, 8:00pm Saturday or 3:00am Wednesday. Casinos can not and do not do this.

Knowing the rules is of great importance when playing any casino game. With slots the rules are very simple: Read the payout chart, insert coins, push button, (or pull handle), insert more coins. If the bells ring and lights flash, open up your pocketbook because you are in the money! Enjoy, but never gamble with more money than you can afford to lose.
Rules for playing Slots
Only slots have so simple rules. In fact it is so because there are no rules at all. All the player has to do is drop coins in the slot and pull the handle or push the spin button. The mission of the game is to match preselected symbols on the pay line, (or paylines, depending on the machine being played, there can be up to 5 pay lines on some machines), to earn credits. Slot machines can be found in many denominations from 5 cents to being the most popular, although there are also machines that accept 0 tokens.
Especially beginners like slots. They don't have to worry about rules and regulations, or being laughed at by the other players for making a bad play, all they have to do is try to hit the jackpot by matching the highest paying symbols on one of the pay lines.

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

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

Classes Of Slot Machines
Slot machines aren't governed by any federal law. Their classifications may vary from state to state. There are restrictions on the type of slot machines that can be used in a casino or other gaming area in some states. The operation of "Class III" (or "traditional") slot machines is fulfilled from a centralized computer system. The chance of winning any payout is the same with every play. You can find Class III slots in Nevada or Atlantic City more frequently. They are also called "Vegas-style slots".
There are "Class II" slot machines ("video lottery terminals" or "VLTs") which are connected to a centralized computer system. The outcome of each wager is determined by it. Each machine has an equal chance of winning a series of limited prizes. The casino pays a fee to the state for each Class III game. Class II games are not so tightly regulated by the state.

Characteristics Of Class II Games
The player is playing not against the casino but against other players. Their competition is for a common prize. There is necessarily a winner in each game. Only when there is a winner the game stops. 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. The same set of numbers is played by all players.

Characteristics Of Class III Games
The house plays against the player. There is no connection between the previous and the next games. The outcome of any game is unpredictable.

Clubs Of Slot Players
Free memberships in "slot clubs" is offered by many American casinos. They offer to return a small fraction of the amount of money that is bet in the form of comps. A member of such club should use cards to insert into the slot machines. Comps or "cash back" from these clubs makes significant differences in the maximum theoretical returns.

Slots In Australia
One of the most popular Australian poker machine games is Queen of the Nile. Slot machines in Australia are officially termed Gaming Machines. Australian-style gaming machines frequently use video displays to simulate physical reels. There are usually five of them. There are laws regulating the use of gaming machines in Australia which are created by State governments.
Gaming machines are found in casinos as well as pubs and clubs in some states. This style of gambling was legalized first in New South Wales. Their legalization in all registered clubs in the state was in 1956.
Only particular forms of gaming machine are permitted to be used in Western Australia.

Slots In The United Kingdom
The terms fruit machines, one-armed bandits and AWP are used to denote slot machines in Britain. There are fruit machines 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. If certain combinations of fruit appear, winnings are paid from the machine. These machines and slot machines seen in casinos and elsewhere around the world are very similar. These games have lots of extra features. However, the jackpots from these fruit machines are strictly limited. The UK fruit machines have some features. 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 can be also given to a player. A nudge is a single-step rotation of a reel of the player's choice.
The maximum payout for an individual game depends on the type and the location of the machine. Private members' clubs are allowed to have "club machines". They charge more per game and have higher jackpots.
These machines also operate in a different manner to American slot machines. The probability of getting the jackpot in each game is independent of any other game.
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. Their ancestor is the traditional Japanese pachinko game. Slot machines are a fairly new phenomenon. They can be found in mostly in pachinko parlors and the adult sections of amusement arcades, known as game centers.
The machines are regulated with IC chips. They have 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.
Carmichael, now 53, had a long history of inventing devices to cheat slot machines. His first invention worked, but not for a long period of time as he was sentenced to prison for using it. After the release Tommy began to invent new kinds of devices for cheating slot machines. For example, he invented a tool called a slider made from guitar wire that he used to insert into the machine and trip a switch, which released coins from the hopper.
When the slots were computerized he needed a new tool. He fooled a manufacturer into believing he was a customer and showing him the inside of a slot machine. It was enough to learn everything that he wanted. 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. 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 that time the police already have all necessary clues to prove that Tommy was guilty. He got three years’ probation and lost everything that he had bought before. He has been banned from entering any casino.