The Yealink T4 Series represents the cutting edge of VoIP technology and is intended for discerning users with extremely high expectations for IP Phones. Revolutionary in appearance and technical design. the T4 is pleasurable and practical t use. advance features include support for gigabit networks, rich programmable DSS keys that tailor the IP Phone features to specific needs and support for Bluetooth headsets that give users more freedom at work. Enhance sound quality is delivered by the Optima HD Voice system. witch meets TIA 920 certification standards. Yealink T4 series is the ideal marriage of perfection and performance.