Features of the MBOX MK3 include: -- The ability to communicate through dial-in phone line or Ethernet, with multiple back up numbers to insure connectivity -- Improved diagnostics and a backlit display for low light installations -- Easy to use with any type of telephone or PBX system on-hold interface -- Increased volume, delivering 1.0 Vrms line level output, a 40% increase over previous designs -- Independent volume controls for messages and music in a two zone configuration -- Enterprise network support including proxy authentication, firewall and content filter compatibility and a security-hardened network interface design