Yealink SIP-T57W IP Phone - Corded - Corded/Cordless - Wi-Fi, Bluetooth - Wall Mountable, Desktop - Classic Gray - VoIP - IEEE 802.11a/b/g/n/ac - Caller ID - Speakerphone - 2 x Network (RJ-45) - USB - PoE Ports - Color - SIP, SIP v2, RTCP XR, RTCP XR, LDAP, NAT, STUN, DHCP, PPPoE, SNTP, UDP, ... Protocol(s):