IVR
An IVR (interactive voice response) system is an automated phone menu that plays recorded prompts and routes callers based on the keys they press or the words they say.
Also called: interactive voice response, phone tree, auto-attendant
"Press 1 for sales, 2 for support." An IVR answers the line, plays a menu, and acts on the caller’s response, sending them to a department, reading back an account balance, or taking a message. The simplest IVRs recognize only keypad tones; more recent ones accept a handful of spoken keywords.
IVRs are stateless. Each prompt is a fresh decision point with no memory of what the caller said two menus ago, which is why a caller who chose the wrong branch has to hang up or start again. The menu is fixed in advance, so anything outside it, an unusual question, two requests at once, has nowhere to go.
That rigidity is the contrast people have in mind when they compare a phone tree with a conversational agent, which follows the caller rather than a script.