T41S VoIP Skype for Business (SfB) telephone, 2 x Fast Ethernet, 15 keys (3 pages of 5 keys), PoE required, AC optional, 2.7 inch backlit LCD, HD audio, RJ9 headset jack, EHS support for specific Jabra and specific Plantronics headsets (cable required), 1 x USB, WiFi support (requires adapter), Bluetooth support (requires adapter), Opus audio codec support. Optional AC power supply.