This duplex extension enables connection of two telephones or accessories. It easily extends the reach from outlet to your devices. Designed for superior signal transmission and maximum compatibility. Connects Devices (From/To): Telephone, Telephone Accessory to Modular Phone Wall Outlet; Connector/Port: 6P4C Plug, Dual Jack; For Device Type: Telephone, Telephone Accessory; Cable Type: Duplex Outlet Line Extension Cord.