Two Cords, One Device. This retractable network AND phone cord unit is the perfect mobile solution for those seeking connectivity in a compact design. Use the Network Cable System to manage your Cat5 & ISDN cords. Includes three adapters - two that convert the Cat5 (RJ-45) plugs to a standard phone line (RJ-11) plug and a duplex adapter that connects two lines to a single wall jack. The adapters are stored conveniently in the housing itself when traveling.