Slot machines seem simple enough. Pull a handle, the reels spin and either you win or lose. That’s the basic experience for the player but ‘under the hood‘ there are important differences between several types of devices that are often identified as ‘slot machines‘. We’ve written some articles about the difference between ‘Class II’ and ‘Class III’ slots but there’s another important ‘class distinction‘ that you need to be aware of–the video lottery terminal or ‘VLT’. These are very common in a number of states and have their own unique characteristics.

We’ll start with the traditional slot machine or, more appropriately, the ‘Class III‘ slot machine since its the easiest to explain. The ‘Class III’ slot machine is the type of device that you’ll find in Las Vegas casinos. Most real money online slot machines operate as Class III machines. The class divisions are derived from The Indian Gaming Regulatory Act which sets US Federal guidelines for tribal gaming activities. The Indian Gambling Regulatory Act establishes three classes of games. Class I gaming is defined as “traditional Indian gaming, which may be part of tribal ceremonies and celebrations” and social gaming for minimal prizes. This class falls under the jurisdiction of individual tribal councils and isn’t applicable to slot machines.

Class III is traditional ‘Las Vegas’ or ‘casino-style’ gambling. The table games like roulette, blackjack and craps would all fall under Class III as would the slot machines and video poker games you’d find in any Las Vegas casino. As far as it concerns slot machines, these are the RNG based games that we’ve described in the previous content in this section. While each individual machine is programmed to pay back a certain percentage of what it takes in it is otherwise completely random. You have the possibility of winning a jackpot on any spin of the wheel if the random numbers generated by the machine fall in your favor.

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Bingo‘ slot machines are another name for what is more appropriately referred to as a ‘Class II’ slot machine. Class II slot machines are machines that operate in such a way to be legal under the Indian Gaming Regulatory Act’s definition which essentially refers to Bingo games. More specifically, the act defines Class II as “the game commonly known as bingo (whether or not electronic, computer, or other technological aids are used in connection therewith) and, if played in the same location as the bingo, pull tabs, punch board, tip jars, instant bingo, and other games similar to bingo.

At one point in history, many tribes operated large high stakes bingo games in warehouse-sized halls. A few tribes still specialize in this type of bingo and others include traditional bingo in their casino properties. The desire of tribes to further leverage their gaming operations and the necessity to compete with other forms of gambling led to the creation of the ‘Class II slot machine‘.

The Class II Slot Machine falls into the part of the Indian Gaming Regulatory Act definition that permits ‘electronic, computer or other technological aids‘ used in conjunction with a bingo game. Class II machines are in many ways indistinguishable from their Class III cousins. In fact, many of the same popular titles you’d see in a Las Vegas casino will be found in a Class III property. The big difference is that the results of each spin are based on electronic bingo games involving multiple machines throughout the casino. These bingo games are conducted in the background while the player experiences a virtually identical slot machine experience that they’d have on a Class III machine. The machine doesn’t use a random number generator like a ‘Class III‘ machine–instead when you spin the reels you’re entered into some type of bingo game with other players in the casino (some have a proprietary format making it all the vaguer). The results of this ‘bingo game‘ that happens completely in the background determines the reel pattern and if you win or lose.


Video Lottery Terminals or ‘VLT’s’ are increasingly common in some states with lottery operations. As the name suggests, they are video gaming machines run by the state lottery. Lotteries that offer these games include versions of slot machines, video poker, video keno, etc. These games may look the same from state to state but many operate differently.

In fact, it’s impossible to generalize how ‘VLT’s’ operate. In Oregon and South Dakota, the VLTs found in bars and similar locations are ‘Las Vegas-style‘ Class III machines operating from a random number generator (RNG) within the device itself. In other states, the games are random but get their results from a central processing center. The randomization takes place at this central location and allows the lottery to monitor in real time win rates and jackpot distribution. Still, other lotteries have VLT’s that are more like video versions of scratch cards or video ‘pull tab‘ machines. With these machines every hand/spin/deal or whatever is ‘predetermined‘. It doesn’t matter how much these devices *look* like slot or video poker machines–the player has no control over the outcome in the same way that he has no control over a scratch-off ticket. He just initiates the process to reveal the ‘outcome‘.

The problem is that states don’t go out of their way to reveal how their video lottery devices work ‘under the hood‘ which means the players are unable to know exactly how the outcomes are determined. In theory, it may not matter–winning percentages are often similar from one type to another and the ultimate outcome is ‘you pay your money, you take your chance‘. Some gamblers, however, object to the lack of transparency and suggest that the player has a right to know if a game is completely random and if so how that ‘randomness’ is derived.