X3U Pro Enterprise IP Phone As an ideal cost-effective Gigabit IP phone, Fanvil X3U provides the direct access to instructions with the intuitive design of high-resolution color display and newly increased line keys, offering you greater flexibility, productivity, to exceed the different demands of businesses. Wideband codec of G.722 and Opus in this device deliver you an immersive HD audio experience in both high band and low band with the network.