- Cortelco VoIP telephone- The feature rich 2757 has undergone extensive 3rd party interoperability testing at tekVizion LABS and was recently issued an official statement of certification as "SIP Verified to Cisco Unified Call Manager 5.0"- WAN port: 1 xRF45 10/100 Base-T Ethernet, line auto-sensing/switching - PC port: 1 x RJ45 10/100 Base-T Ethernet, line auto-sensing/switching - LCD: dot matrix (2.75" x 1.5") - 4 Soft-buttons plus navigation button - Supports G.723.1, G.729a/b, G.711 voice codecs - Complies with RFC-3261, SIP standard - Multi-protocol support: TFTP, RTP, SNTP, HTTP, SIP, DHCP, PPPoE, and Telnet - Dynamic IP support (DHCP and PPPoE) - Remote software upgrade capability (via FTP or TFTP) - QoS support - STUN support - Caller ID - Web based GUI setup - Multi-line (4-line appearance buttons with LED's) - Call transfer - 3-Way conference - Hold - DND - Message waiting indicator - Call history - Phonebook - 5 One-touch memory - Redial - Speakerphone - Headset compatible - Audible/visual ring signal - Adjustable ring volume - Selectable ringer tones - Handset volume control - PoE (power-over-ethernet) - Optional AC power adapter (ITT-2757-ACP)- Two position phone stand - BlackITT2757VOIP