Grandstream GXP1615 IP Phone is an entry-level business phone that supports 1 SIP account and 2-line keys with Power Over Ethernet (PoE). This user-friendly IP Phone is packed with many VoIP features at an affordable price. Grandstream GXP1615 IP Phone Features and Specifications. 2-line keys and 1 SIP account. Power over Ethernet (PoE) and power supply included. 132 x 48 LCD screen. 3 XML programmable softkeys. 10/100 mbps ports. 3-way audio conferencing. Full-duplex speakerphone with HD audio. EHS support for Plantronics headsets. Multi-language support.