IVR stands for Interactive Voice Response, a technology that automates routine customer service interactions by allowing callers to interact using touch tone digits. It's a phone menu or phone tree. A basic example of an IVR application is an automated attendant or voice menu: callers are presented with a recorded menu and respond by selecting a digit or, in some cases, by entering an extension number. The automated attendant eliminates the need for a live operator to handle the call.

More complex applications include prescription refill for pharmacies, password reset, voice surveys, account balance inquiries, flight status checks, package tracking, pre-sales qualification questionnaires, etc. The key idea is to automate a routine, repetitive task that would otherwise require the time and effort of an employee. The savings potential gives IVR solutions a very rapid return on investment (ROI), as on server can potentially eliminate multiple live agents.

IVR systems are historically sold at a premium, to large degree because of the strong ROI. A system with four ports (and thus capable of processing four concurrent calls) could cost thousands of dollars. Like conference bridging, voice messaging and other communications applications, IVR is generally an add-on component for a traditional phone system.

IVR is standard equipment with a Cooler Master PBX.