Based on SIP,Website:http://www.voipphonetech.com, the Cisco SPA303 IP Phone provides comprehensive interoperability with equipment from voice over IP (VoIP) infrastructure leaders, enabling service providers to quickly roll out competitive, feature-rich services to their customers.FeaturesPixel-based monochrome display (128 x 64)3-line business class phone with line indication4-soft key buttons and 4 way navigational clusterFixed features include mute, headset, speakerphone, and holdMessage retrieval key with message waiting lightHigh quality microphone and speakerIntegrated 2.5 mm headset jack2-port 10/100BASE-T switch for collocated PCIncludes 5V AC power supply; not PoE compatibleCompatibilitySIP compatible for use with open source IP PBX platforms and hosted telephony solutionsSPCP compatible for use with Cisco Unified Communications 300 (UC300) and 500 (UC500) Series for Small BusinessCONDITION: BRAND NEWWARRANTY: 1-YEAR