Mitel 5224 IP System Telephone - RefurbishedSupport for SIP and MiNET Protocols Handsfree operation (full duplex) 24 programmable multi function keys with dual color LED indicators* (for speed dialing, line appearances, feature access) Eight function keys: Hold, Superkey, Message, Speaker,Mute, Transfer Conference, Redial, Cancel Three context sensitive softkeys for intuitive feature access Two line, 20 character white, backlit, graphics display, with auto dimming Superkey programming for easy