Kramer Electronics 648 648 is a high performance bi-directional optical repeater for FireWire 1394a and 1394b signals. When used in pairs, it will extend the distance of FireWire cable runs up to 500 meters. FireWire Ports - 2 bilingual 9-pin IEEE 1394b 800Mbps. Optical Ports - 2 duplex LC Fiber connectors. Range - Extends Firewire cable range from 14.5 ft (4.5 meters) to up to 1640 ft (500 meters) between 2 units. Transfer Rate - 100, 200, 400 and 800Mbps. Compact DigiTOOLS - 3 units can be rack mounted side-by-side in a 1U rack space with the optional RK-3T rack.