A 5-pin DMX terminator is used to stabilize DMX512-A signal transmission by preventing signal reflections at the end of a DMX chain. It plugs into the last fixture or device in a DMX line and contains a 120-ohm resistor between the data lines, matching the impedance of DMX cables. This helps maintain signal integrity, especially in longer runs or complex lighting setups. The 5-pin configuration supports full DMX protocol, including auxiliary data channels, and is typically used in professional lighting systems where reliable communication is critical. Terminators are passive devices and do not require power.