Telephony Features              ● One voice line              ● Music on hold*              ● Call waiting              ● Outbound caller ID blocking**               ● Call transfer: attended and blind** ( SIP Only )              ● Three-way call conferencing with local mixing              ● Multiparty conferencing via external conference bridge              ● Automatic redial of last calling and last called numbers               ● Call pickup: selective and group*              ● Call swap               ● Call back on busy**               ● Call blocking: anonymous and selective**               ● Call forwarding: unconditional, no answer, and on busy**               ● Hot line and warm line automatic calling               ● Digits dialed with number auto-completion               ● Anonymous caller blocking**               ● Support for Uniform Resource Identifier (URI) (IP) dialing (vanity numbers)               ● Multiple ring tones with selectable ring tone per line                ● Call duration and start time stored in call logs in web GUI               ● Distinctive ringing based on calling and called number               ● 10 user-downloadable ring tones               ● Speed dialing, eight entries               ● Configurable dial/numbering plan support               ● Intercom*               ● Group paging               ● Network Address Translation (NAT) Traversal, including Serial Tunnel (STUN) support                ● DNS SRV and multiple A records for proxy lookup and proxy redundancy               ● Syslog, debug, report generation, and event logging               ● Support for highly secure encrypted voice communications                ● Built-in web server for administration and configuration, with multiple security levels               ● Automated remote provisioning, multiple methods; up to 256 bit encryption (HTTP, HTTPS, Trivial File  Transfer Protocol [TFTP])               ● Option to require administrator password to reset unit to factory defaults  |              Hardware Features              ● Voicemail message waiting indicator light              ● Voicemail message retrieval button              ● Volume control               ● Redial Button              ● Flash Button              ● Standard 12-button dialing pad              ● High-quality handset               ● One Ethernet WAN port 10/100BASE-T RJ-45              ● 5 VDC universal (100–240V) switching power adaptor included              Regulatory Compliance              ● FCC (Part 15, Class B) ,UL, CE Mark, A-Tick               Security Features              ● Password-protected system, preset to factory defaults              ● Password-protected access to administrator and user-level features              ● HTTPS with factory-installed client certificate              ● HTTP digest: encrypted authentication via MD5 (RFC 1321)              ● Up to 256-bit Advanced Encryption Standard (AES) encryptio  |