T31P VoIP SIP telephone, 2 x Fast Ethernet, 2 x line keys, PoE required, AC optional, 2.3 inch backlit LCD, HD audio, RJ9 headset jack. This makes it useful for replacement parts, workstation setup, shared office areas and inventory replenishment. The Voip Two Line Phone gives buyers a clear option for phone, headset or communication equipment needs. It is useful for replacement parts, workstation setup, shared office areas and inventory replenishment.