Definition: TUI

(Telephone User Interface) The combination of Touch-tone input from the telephone keypad coupled with speech output from the connected voicemail or IVR application. While early speech technology was struggling to recognize voice utterances for voice control and data entry, the ubiquitous Touch-tone keypad was a practical solution. It works with enterprise telephone networks, the PSTN, public payphones and traditional cellphones. Its centerpiece is the standard 12-key keypad and conventions such as using the pound key for "enter," the star key for "up one level" or "escape," and "1" for yes, "2" for no.