SMPTE (pronounced sim-tee) when discussed in lighting systems usually refers to SMPTE Timecode.
Timecode is a way to synchronise events throughout a system based on time. It was originally developed by the Society of Motion Picture and Television Engineers for time synchronisation across film and TV recordings.
SMPTE is available in several ETC consoles. SMPTE is transmitted as an audio signal, and is input to the consoles as an audio signal, usually using standard phono, 1/4" jack, or 3-pin XLR connectors.
SMPTE encodes a time as hours, minutes, seconds and frames. The number of frames per second can vary depending on the time code format in use.
ETC Lighting consoles typically allow an event (playback go, macro), to be fired at a given timecode time.