A SCSI Terminator is a device used in SCSI (Small Computer System Interface) networks to prevent signal reflections on the data bus. It is essential for maintaining data integrity by ensuring that the electrical signals can travel without interference. Terminators are typically placed at both ends of a SCSI chain, which connects multiple devices like hard drives and scanners. Without proper termination, signals can bounce back along the cable, causing data errors and communication failures. There are two main types of SCSI terminators: passive and active. Passive terminators simply connect the signal lines to ground, while active terminators use electronic components to provide better signal quality.