Slot Machine

A slot machine (American English), fruit machine (British English), or poker machine (Australian English) is a certain type of casino game. Traditional slot machines are coin-operated machines with three or more reels, which spin when a lever on the side of the machine is pulled. The machines include a currency detector that validates the coin or money inserted to play. (The slot machine is also known informally as a one-armed bandit because of its traditional appearance and its ability to leave the gamer penniless.) The machine typically pays off based on patterns of symbols visible on the front of the machine when it stops. Modern computer technology has resulted in many variations on the slot machine concept. Today, slot machines are the most popular gambling method in casinos and constitute about 70% of the average casino's income.

History

Sittman and Pitt of Brooklyn, New York developed a gambling machine in 1891 that could be considered a precursor to the modern slot machine. It contained 5 drums holding a total of 50 card faces and was based on poker. This machine proved extremely popular and soon there was hardly a bar in the city that didn't have one or more of the machines bar-side. Players would insert a nickel and pull a lever, which would spin the drums and the cards they held, the player hoping for a good poker hand. There was no direct payout mechanism, so a pair of Kings might get the player a free beer, whereas a Royal Flush could pay out cigars or drinks, the prizes wholly dependent on what was on offer at the local establishment. To make the odds better for the house, two cards were typically removed from the "deck": the Ten of Spades and the Jack of Hearts, which cut the odds of winning a Royal Flush by half. The drums could also be re-arranged to further reduce a player's chance of winning.

The first "one-armed bandit" was invented in 1887 by Charles Fey of San Francisco, California, who devised a much simpler automatic mechanism. Due to the vast number of possible wins with the original poker card-based game, it proved practically impossible to come up with a way to make a machine capable of making an automatic pay-out for all possible winning combinations. Charles Fey devised a machine with three spinning reels containing a total of five symbols – horseshoes, diamonds, spades, hearts and a Liberty Bell, which also gave the machine its name. By replacing ten cards with five symbols and using three reels instead of five drums, the complexity of reading a win was considerably reduced, allowing Fey to devise an effective automatic payout mechanism. Three bells in a row produced the biggest payoff, ten nickels. Liberty Bell was a huge success and spawned a thriving mechanical gaming device industry. Even when the use of these gambling devices was banned in his home state after a few years, Fey still couldn't keep up with demand for the game elsewhere.

Another early machine gave out winnings in the form of fruit flavoured chewing gums with pictures of the flavours as symbols on the reels. The popular cherry and melon symbols derive from this machine. The "BAR" symbol now common in slot machines was derived from an early logo of the Bell-Fruit Gum Company. In 1964, Bally developed the first fully electromechanical slot machine called Money Honey.

Description

A person playing a slot machine purchases the right to play by inserting coins, cash, or in newer machines, a bar-coded paper ticket (known as "ticket in/ticket out" machines), into a designated slot on the machine. The machine is then activated by means of a lever or button, or on newer machines, by pressing a touchscreen on its face. The game itself may or may not involve skill on the player's part — or it may create the illusion of involving skill without actually being anything else than a game of chance.

The object of the game is to win money from the machine. The game usually involves matching symbols, either on mechanical reels that spin and stop to reveal one or several symbols, or on a video screen. The symbols are usually brightly colored and easily recognizable, such as images of fruits, and simple shapes such as bells, diamonds, or hearts.

Most games have a variety of winning combinations of symbols, often posted on the face of the machine. If a player matches a combination according to the rules of the game, the slot machine pays the player cash or some other sort of value, such as extra games.

There are many different kinds of gambling slot machines in places such as Las Vegas. Some of the most popular are the video poker machines, in which players hope to obtain a set of symbols corresponding to a winning poker hand. Depending on the machine, players can play one, 100, or more hands at one time.

Becoming more popular now are the multi-line slots. These slots have more than one payline. Reel slots commonly have three or five paylines, while video slots have 9, 15, 25, or even 100 different paylines. Video slots are themed slots, with graphics and music based on popular entertainers or TV programs (The Addams Family, I Dream of Jeannie, etc.) with a bonus round. Most accept variable amounts of credit to play with 1 to 5 credits per line being typical. The higher the amount bet, the higher the payout will be. Of course, there are the standard 3 - 5 reel slot machines, of various types. These are the typical "one-armed bandits".

One of the main differences between video slots and reel slots is in the way payouts are calculated. With reel slots, the only way to win the maximum jackpot is to play the maximum number of coins (usually 3, sometimes 4, or even 5 coins per spin). With video slots, the fixed payout values are multiplied by the number of coins per line that are being bet. In other words: on a reel slot, it is to the player's advantage to play with the maximum number of coins available. On video slots, it is recommended to play as many individual lines as possible, but there is no benefit to the player in betting more than one credit per line with regards to calculating the payout amounts. (There are some isolated cases where a video slot machine requires the maximum number of credits per spin to be inserted to win the largest payout, but those are the exception.) An example: On the "Wheel of Fortune" reel slot, the player must play 3 coins per spin to be eligible to trigger the bonus round and possibly win the jackpot. On the Wheel of Fortune video slot, the chances of triggering the bonus round or winning the maximum jackpot are exactly the same regardless of the number of coins bet on each line.

Larger casinos offer slot machines with denominations from $.01 (penny slots) all the way up to $100.00 or more per credit. Large denomination slot machines are usually cordoned off from the rest of the casino into a "High Limit" area, often with a separate team of hosts to cater to the needs of the high-rollers who play there.

Slot machines common in casinos at this time are more complicated. Most allow players to accept their winnings as credits, which may be "spent" on additional spins.

In the last few years, new slot machines commonly known as "multi-denomination" have been introduced. In a multi-denomination slot machine, the player can choose the value of each credit wagered from a list of options. Based upon the player's selection, the slot machine automatically calculates the number of credits the player receives in exchange for the cash inserted and displays the amount of available credits to the player. (For example, a player could choose to wager one dollar per game on a nickel slot machine.) This eliminates the need for a player to find a specific denomination of a particular slot machine; they can concentrate on simply finding the machine and setting the denomination once they decide to play.

Recently, some casinos have chosen to take advantage of a concept commonly known as "tokenization": 1 token buys more than one credit. A casino can configure slot machines of numerous different denominations to accept the same type of token. (For example, all penny, nickel, quarter, and dollar slot machines could be configured to accept dollar tokens.) This significantly reduces a casino's inventory costs and coin handling costs. A tokenized slot machine automatically calculates the number of credits the player receives in exchange for the token inserted and displays the amount of available credits to the player. When a player chooses to collect his credits (by pressing a "Cash Out" button), the slot machine will automatically divide the number of credits on the credit meter by the value of one token and return the result to the patron. Any remainder is known as "residual credits" and cannot be collected. Residual credits must be either played or abandoned.

Terminology

Bonus is a special feature of the particular game theme, which is activated when certain symbols appear in a winning combination. In the bonus, the player is presented with several items on a screen from which to choose. As the player chooses items, a number of credits is revealed and awarded. Some bonuses use a mechanical device, such as a spinning wheel, that works in conjunction with the bonus to display the amount won.

Candle is a light on top of the slot machine. It flashes to alert the operator that change is needed, hand pay is requested or a potential problem with the machine.

Carousel refers to a grouping of slot machines, usually in a circle or oval formation.

Coin hopper is a container where the coins that are immediately available for payouts are held. The hopper is a mechanical device that rotates coins into the coin tray when a player collects credits/coins (by pressing a "Cash Out" button). When a certain preset coin capacity is reached, a coin diverter automatically redirects, or "drops", excess coin into a "drop bucket" or "drop box".

Credit meter is a visual L.E.D. display of the amount of money or credits on the machine.

Drop bucket or drop box is a container located in a slot machine's base where excess coins are diverted from the hopper. Typically, a drop bucket is used for low denomination slot machines and a drop box is used for high denomination slot machines. A drop box contains a hinged lid with one or more locks whereas a drop bucket does not contain a lid. The contents of drop buckets and drop boxes are collected and counted by the casino on a scheduled basis.

EGM is used as a short-hand for "Electronic Gaming Machine".

Hand pay refers to a payout made by a slot attendant or cage, rather than the slot machine. A hand pay occurs when the amount of the payout exceeds the maximum amount that was preset by the slot machine's operator. Usually, the maximum amount is set at the level where the operator must begin to deduct taxes. A hand pay could also be necessary as a result of a short pay.

Hopper fill slip is a document used to record the replenishments of the coin in the coin hopper after it becomes depleted as a result of making payouts to players. The slip indicates the amount of coin placed into the hoppers, as well as the signatures of the employees involved in the transaction, the slot machine number and the location and the date.

Low Level or Slant Top slot machines include a stool so you can sit and play. Stand Up or Upright slot machines are played while standing.

Optimal play is a payback percentage based on a gambler using the optimal strategy in a skill-based slot machine game.

Payline is a straight or zig-zagged line that crosses through one symbol on each reel, along which a winning combination is evaluated. Classic spinning reel machines usually have up to nine paylines, while video slot machines may have as many as one hundred.

Rollup is the process of dramatizing a win by playing sounds while the meters count up to the amount that has been won.

Short pay refers to a partial payout made by a slot machine, which is less than the amount due to the player. This occurs if the coin hopper has been depleted as a result of making earlier payouts to players. The remaining amount due to the player is either paid as a hand pay or an attendant will come and re-fill the machine.

Tilt In the old mechanical days, slot machines had tilt switches. While modern machines no longer have tilt switches, any kind of mechanical failure (door switch in the wrong state, reel motor failure, etc) is still called a "tilt".

Theoretical Hold Worksheet is a document provided by the manufacturer for all slot machines, which indicates the theoretical percentage that the slot machine should hold based on adequate levels of coin-in. The worksheet also indicates the reel strip settings, number of coins that may be played, the payout schedule, the number of reels and other information descriptive of the particular type of slot machine.

Weight count is an American term, referring to the dollar amount of coins or tokens removed from a slot machine's drop bucket or drop box and counted by the casino's hard count team through the use of a weigh scale.

Pay table

Each machine has a table that lists the number of credits the player will receive if the symbols listed on the pay table line up on the pay line of the machine. Some symbols are wild and will pay if they are visible in any position, even if they are not on the pay line. Especially on older machines, the pay table is listed on the face of the machine, usually above and below the area containing the wheels. Most video machines display the pay table when the player presses a "pay table" button or touches "pay table" on the screen; some have the pay table listed on the cabinet as well. Technology

Random number generator

It is a common belief that the odds on a machine have something to do with the number of each kind of symbol on each reel, but in modern slot machines this is no longer the case. Modern slot machines are computerized, so that 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. The positions the reels will come to rest on are chosen by a Random Number Generator (RNG) contained in the machine's software.

The RNG is constantly generating random numbers, at a rate of hundreds or maybe thousands per second. As soon as the lever is pulled or the "Play" button is pressed, the most recent random number is used to determine the result. This means that the result varies depending on exactly when the game is played. A fraction of a second earlier or later, and the result would be different.

Some professional gamblers observe that the RNG does not actually generate random numbers. Indeed, all RNG (also called Pseudorandom Number Generators or PRNGs) will eventually repeat their number sequence. This behavior is due to poor programming, as it is relatively easy to build PRNGs with periods so long no computer could complete a single period in the expected lifetime of the universe. Having access to the PRNG code and seed values Ronald Dale Harris, a former slot machine programmer, discovered equations for specific gambling games like Keno that allowed them to predict what the next set of selected numbers would be based on the previous games played.

Payout percentage

Slot machines are typically programmed to pay out as winnings between 82 to 98 percent of the money that is wagered by players. This is known as the "theoretical payout percentage". The minimum theoretical payout percentage varies among jurisdictions and is typically established by law or regulation. For example, the minimum payout percentage in Nevada is 75 percent and in New Jersey is 78 percent. The winning patterns on slot machines, the amounts they pay, and the frequency at which they appear are carefully selected to yield a certain percentage of the cost of play to the "house" (the operator of the slot machine), while returning the rest to the player during play. Suppose that a certain slot machine costs $1 per spin. It can be calculated that over a sufficiently long period, such as 1,000,000 spins, that the machine will return an average of $950,000 to its players, who have inserted $1,000,000 during that time. In this (simplified) example, the slot machine is said to pay out 95%. The operator keeps the remaining $50,000. Within some EGM-development organizations this concept is referred to simply as "par". "Par" also manifests itself to gamblers as promotional techiniques: "Our 'Loose Slots' have a 93% Pay-back! Play now!" As an aside, the "Loose Slots" actually may describe an anonymous machine in a particular bank of EGMS.

A slot machine's theoretical payout percentage is set at the factory when the software is written. Changing the payout percentages after a slot machine has been placed on the gaming floor requires a physical swap of the software, which is usually stored on an EPROM but may be downloaded to Non-Volatile Random Access Memory (NVRAM) or even stored on CD-ROM or DVD depending on the technological capabilities of the machine and the regulations of the jurisdiction. Based on current technology, this is a time consuming process and as such is done infrequently. In certain jurisdictions, such as New Jersey, the EPROM is sealed with a tamper-evident seal and can only be changed in the presence of Gaming Control Board officials. Other jurisdictions, including Nevada, randomly audit slot machines to ensure that they contain only approved software.

In many markets where central monitoring and control systems are used to link machines for auditing and security purposes, usually in wide area networks of multiple venues and thousands of machines, player return must usually be changed from a central computer rather than at each individual machine. A range of percentages are preprogrammed into the game software and selected by configuring the machine remotely.

In 2006, the Nevada Gaming Commission began working with Las Vegas casinos on technology that would allow the casino's slot manager to change the game, the odds, and the payouts remotely via a computer. 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.

Linked machines

Often machines are linked together in a way that allows a group of machines to offer a particularly large prize, or "jackpot". Each slot machine in the group contributes a small amount to this progressive jackpot, which is awarded to a player who gets (for example) a royal flush on a video poker machine, or a specific combination of symbols on a regular or 9 line slot machine. 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 machines may be owned by the machine maker who is responsible for paying the jackpot. The casinos lease the machines rather than owning them outright. Megabucks may be the best known example of this type of machine. Megabucks Nevada starts at $10,000,000 after a jackpot. (Prior to September 2005, Megabucks Nevada reset to $7,000,000.) The new penny Megabucks video game also has a jackpot that starts at $10,000,000.

Slot machines that are not linked to a large regional jackpot such as Megabucks usually have higher payout percentages, as linked machines have to take into consideration the large jackpot amount into their payout percentage calculations.

Near-miss programming

Because 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. For instance, if the jackpot combination is "7-7-7", a slot machine could be programmed to frequently display "7-7-(non-7)". This can fool the player into thinking they "almost won", Teasing them into playing more often.

This practice of showing combinations that are similar to winning combinations more frequently than would occur randomly is called "near-miss" programming. It has been ruled illegal in the U.S. states of Nevada and New Jersey. The Nevada Gaming Commission did review some machines with this type of programming and refused to authorize them.

There is a related phenomenon that is also sometimes called "near-miss". The chance of a winning combination appearing on a payline is controlled by the winning percentages programmed into the slot machine. However, the combinations appearing 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 payline than on the payline. Using the same example above, it is much more likely that a "winning combination" of "7-7-7" would appear on a line above or below the payline than the chance that it would appear on the payline. This phenomenon only occurs where abbreviated physical reels are used to display a win pattern based upon the RNG. In Video Slot Machines, virtual reels are used and the symbols that appear around the winning line are usually an accurate depiction of how the reels where mathematically modeled.

The issue of a near-miss above or below the payline was also investigated by the Nevada Gaming Commission. They ruled that this was legal, so long as the "near-miss" above or below the payline was not specially programmed. In other words, the "near-miss" must be just as likely to occur as any other combination. The machine cannot be specially programmed to show "winning combinations" more frequently than other combinations above or below the payline.

The calculation is more complicated than implied here. The stops are not 'programmed' in the sense that their outcome is the result of a calculation. In fact, the reel strips (like a mechanical poker machine) are designed so that the machine will pay according to the relevant RTP.

Near-miss programming, where a near miss is inaccurately displayed (i.e. the player is shown something that is not an accurate representation of the reelstrips) is not allowed in Australia either. Due to this, regulators use stop motion cameras to audit manufacturer's practices.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Slot machine".