Optical isolation is a critical safety and performance feature in arcade machine controls, designed to protect sensitive components from high voltages and electrical noise. The most common types include optocouplers and optical switches. Optocouplers, or opto-isolators, use an LED and a phototransistor to transmit signals across an electrical barrier, preventing ground loops and voltage spikes from damaging the main printed circuit board (PCB). They are frequently found in coin door mechanisms, control panel interfaces, and power supply feedback circuits. Optical switches, another prevalent type, employ an infrared LED and a phototransistor to detect the interruption of light, commonly used for joystick movement detection and button inputs to eliminate physical contact wear. These isolation methods ensure reliable operation, reduce maintenance needs, and enhance the longevity of arcade cabinets by isolating the control inputs from the high-power electronics.