The Gefen USB 400 FO.S. is a specialized, long-distance USB extension system that utilizes fiber optic technology to overcome the severe distance limitations of traditional copper-based USB 2.0. This system consists of a transmitter unit and a receiver unit, connected by a single multimode fiber optic cable, which together create a virtual 4-port USB hub at a remote location up to 400 meters away. It is engineered for professional AV, industrial, and digital signage applications where a computer must control or communicate with USB peripherals—such as touchscreens, printers, scanners, or license dongles—that are located far beyond the standard 5-meter USB cable limit, without any signal degradation or latency issues associated with long copper runs.

The transmitter unit connects directly to a host computer's USB port and converts the electrical USB signal into an optical one for transmission over the fiber link. The receiver unit, placed at the remote site, converts the optical signal back to a standard electrical USB signal and provides four downstream USB 2.0 Type-A ports for connecting the target peripherals. The system is transparent to the host computer, which detects it as a standard USB hub, ensuring broad compatibility without the need for specialized drivers. This fiber optic approach provides complete immunity to electromagnetic interference (EMI), ground loops, and voltage drop problems, ensuring reliable data transfer for both high-speed (480 Mbps) and low-speed USB devices over the extended distance.

Designed for permanent installation in demanding environments, the system is typically housed in compact, rack-mountable metal enclosures and powered by external adapters. It solves a critical connectivity challenge in large venues, campuses, and industrial settings, enabling centralized control of distributed USB devices. By leveraging fiber optics, the Gefen USB 400 FO.S. delivers reliable, high-performance USB connectivity where conventional extenders fail, making it an essential tool for system integrators designing large-scale, robust technology deployments.