The GB474PTZ Ground-Loop Blocker is an active device used to eliminate Ground Loop Interference and picture quality problems in new and existing CCTV video installations. This product will allow "Up the coax Remote Control Pan, Tilt, and Zoom" operation and will extend the range of the control signal up to 3500 feet. The unit is installed at the monitor site where the CCTV signals come together, or at any intermediate point where video ground-loop problems exist. The GB474PTZ operates with any standard B/W or Color video signal.