Line Keys - 2 lines, 2 concurrent calls per line Speaker Phone - Full duplex speakerphone Ethernet Connectivity - 2 x 10/100/1000 Base-T Display Type - Graphical, backlit multi-lingual LCD (132 X 64) Headset Support - RJ-9 Headset Jack X 1 VoIP and Signaling - SIP over TCP/UDP/TLS, DNS_SRV and more PoE - PoE or external power supply The AudioCodes 400HD series of IP phones includes a range of easy-to-use, feature-rich products for the service provider hosted services, enterprise IP telephony and contact center markets. Based on the same advanced, field-proven underlying technology as our other VoIP products, AudioCodes high quality IP phones enable systems integrators and end-customers to build end-to-end VoIP solutions. This is a special order item. All sales are final.