How Does VoiceXML IVR Work?

A VoiceXML IVR application operates like your traditional web application. However, instead of a web browser (like Firefox or Internet Explorer) presenting an HTML-based web page generated by a web server that, in turn, asks for data from a database, a VoiceXML IVR plays a VoiceXML-based dialog generated by a web server that also asks for data from a database.

Think of it like ordering food at a restaurant. You are presented with a menu of choices by the waiter. After perusing the menu, you settle on a few choices and you communicate these to your waiter. Your waiter takes your order but he or she does not actually cook it all up. Your waiter submits your order to the cook who then grabs various ingredients from the refrigerator and processes the ingredients into a fine set of dishes. The waiter then picks up your dishes, brings them to your table, and serves them to you.

Now instead of a menu, waiter, cook, and refrigerator, we have an IVR server, a call flow application server, a business logic server, and a database. The call flow app server tells the IVR what to say and what to collect from the caller. For instance, the call flow app server might instruct the IVR to ask for an ID number. The caller enters the ID number over the phone and the IVR delivers this number to the call flow app server. The call flow app server, however, does not know what data is associated with this ID number so it has to ask the business logic server for this data. The business logic server knows how to extract this data from the database based on the ID number. Let's say it's an account balance. This value is determined by the business logic server and is relayed to the call flow app server. The call flow app server then builds a VoiceXML script that will instruct the IVR server to state your current account balance.

We refer to this as the VoiceXML IVR four-tier architecture. Plum Voice built the IVR platform (tier one) from the ground up and we specialize in writing custom call flow application server code (tier two). Most of our customers provide tiers three and four on their own as they already own a web server and database that suit those two roles respectively. In general it makes more sense for our customers to write the business logic server code as they have the most knowledge of how their business processes work and how their business data is structured.