Arcade machines rely on modular expansion slots to upgrade and customize their hardware, ensuring compatibility and enhanced gameplay. The most common types include:

1. JAMMA (Japan Amusement Machinery Manufacturers Association) Standard: The industry-standard slot for connecting PCBs (Printed Circuit Boards) to arcade cabinets. It simplifies wiring and supports a wide range of games.

2. PCB Edge Connectors: These slots allow direct insertion of game PCBs, commonly used in older or custom arcade setups. They require precise alignment but offer flexibility.

3. PCI/PCIe Slots: Found in modern arcade machines, these slots enable high-performance upgrades like graphics cards or sound modules for advanced gaming experiences.

4. USB/IO Expansion Slots: Used for adding peripherals like light guns, trackballs, or additional controls, enhancing interactivity.

Understanding these slots helps arcade enthusiasts and technicians maintain, repair, or upgrade machines efficiently. Whether for classic or modern arcades, modular expansion slots are key to versatility and longevity.