How electronic gambling machines work: Structural characteristics

AGRC Discussion Paper No. 8 – July 2017

Appendix: Key terms


The value available for wagering on an EGM. EGMs may have credit values of 1¢, 2¢, 5¢, $1, and so on. EGMs in casinos may permit credit values of higher amounts. The credit value is the value of the minimum bet on the EGM and may be escalated by betting on multiple lines or wagering multiple credits, or both.


Electronic gambling machine. A generic name for any electronic device that permits gambling on a simulated event generated by a random number generator. Other names include slot machines and poker machines ("pokies").


Triggered by a scatter of symbols and consisting of a series of "free" spins, which operate automatically once the user initiates them.

Game maths

The intersection of a machine's reel map and pay table. Represented in a machine's PAR sheet.


A rare event that is triggered by a unique combination of symbols. It can apply to a single machine or to a series of linked machines with an aggregate prize pool.

PAR (sheet)

Probability accounting report. A document maintained by EGM manufacturers which shows a machine's "game maths". Australian machines' PAR sheets are not directly scrutinised or retained by Australian regulators.

Pay table

The prizes awarded for each combination of symbols appearing on a line. For example, if the random process generates three Kings, this will be mapped to the pay table to pay, e.g., five credits.


A series of strips, with symbols, that appears to spin, having its origins in older-style lever-operated machines which spun a series of physical reels.

Reel map

The number and order of symbols on each virtual reel.


Revenue per available customer. An industry term reflecting a design goal (maximising RevPAC) for EGM designers.


Return to player (ratio). The proportion of each wager the EGM is designed to return on average to the user. RTP represents an average deduction from the user's wager for each bet, calculated over the game cycle.


Ticket in–ticket out. A system to allow EGM users to load up a value on a terminal which provides a readable "ticket" on which the value is inscribed. When the session of use is ended, the EGM will then inscribe the value of any remaining credits onto a similar ticket, which may be redeemed at a terminal or via a cashier.


Time on device. The time spent by any given gambler on a given game. An industry term reflecting a design goal (maximising ToD) for EGM designers.