The Avaya 5402 is a cost effective digital telephone, for many office applications. It is designed to complement the 5410 mid-level and 5420 executive telephones. The 5402 has a 2-line by 24-character display with two label-less call appearances, a listen-only speaker, 10 fixed feature keys: Conference, Transfer, Drop, Redial, Speaker, Message, Hold, Mute, Volume Up & Down, and Feature (to access 12 additional dial pad features).

The Avaya 5410 is a flexible display telephone with several capabilities such as local call log and speed dial not available on previous generations of digital telephones.
This telephone provides a 5-line by 29-character display, Conference, Transfer, Drop, Redial, Speaker, Message, Hold, Mute, Volume Up & Down, 12 label-less call appearances, four soft keys, large message waiting indicator, headset jack, local language customization, and eight personalized ring patterns.

The Avaya 5420 Digital Telephone provides a large-scale 7-line by 29-character display for easy viewing and call control with 24 call appearance/feature buttons. The 5420 has all the features of the 5410. Additional features such as call logging and a speed-dial directory help enhance overall productivity by providing users with the tools needed for more effective call tracking and faster outbound calling capabilities.

The Avaya EU24 DSS Module is an add-on unit that works in association with the Avaya 5420 telephone. It provides an additional 24 programmable buttons with associated display label and status icons.