The Best User Interfaces are Based on a Strong Foundation
All IVR applications require Layer 1. Those with speech recognition will want to license the mixed-mode Layer 2, which supports both touch-tone and speech. To fully optimize an IVR application requires Layer 3 technology which eliminates turn-taking problems associated with barge-in, adds intelligence to dynamically adjust the user interface to user preferences, and creates the fastest user-machine dialogue.
Licenses are cumulative; that is, mixed-mode applications require both Layer 1 and Layer 2 technology, and collaboration applications require all three layers.