Yealink T23G IP Phone, 3 Lines. Dual-Port 10/100 Ethernet, 802.3af PoE, Power Adapter Not Included (SIP-T23G). Yealink T23G Professional Gigabit IP Phone. Yealink T23G Features & Highlights Yealink SIP-T23G features intuitive user interface and enhanced functionality which make it easy for people to interact and maximize productivity.