This document discusses VoIP and predictive dialers. It begins with an introduction to VoIP, how it works, and some challenges. It then discusses features of VoIP like making calls anywhere in the world. Predictive dialers are then introduced as widely used in call centers to automatically dial batches of phone numbers for agents. The document explains how predictive dialers work by dialing ahead of available agents to increase productivity by 200-300% compared to manual dialing.