Developed for small and medium businesses, the 5600 Series IP Telephones deliver an extensive set of software features, high audio quality, and an attractive streamlined design. They are simple to use and highly reliable, with sophisticated security capabilities such as media encryption and protection from denial-of-service attacks.

The entry-level 5602 IP Telephone has a 2×24 display, an integrated two-port Ethernet switch, and support for static and dynamic IP address assignment.

The 5610 and 5621 models offer advanced Web-enabled graphical displays, supporting browser-based applications such as online order entry and inventory lookup, in addition to traditional voice applications such as call logging. Both support optional Virtual Private Network (VPN) software, eliminating the need for a VPN device at the remote location.

This phone requires a separate power supply, using either a Avaya 1151D1 or 1151D2 power supply unit and power cord or a 802.3af Power over Ethernet (PoE) source.