Phone Features: Up to 20 simultaneous calls, Up to 10 handsets, Up to 10 SIP accounts, Up to 2 simultaneous calls per handset, Up to 6 repeaters per base station (RT30), Built-in Bluetooth for Bluetooth headset, Personalization: 9 ringer melodies, Screen saver, Multilingual user interface, Network Features: SIP v1 (RFC2543), v2 (RFC3261), SNTP/NTP, VLAN (802.1Q and 802.1P), 802.1x, LLDP, STUN Client (NAT Traversal), UDP/TCP/TLS, IP assignment: Static/DHCP, Security: Open VPN, Transport Layer Security (TLS), HTTPS (server/client), SRTP (RFC3711), Digest authentication, Secure configuration file via AES encryption,