Voip Drupal is a software platform that allows Drupal sites to make phone calls, record audio, conduct voice polls, and more. It includes modules that provide APIs to connect to VoIP servers and manage calls. Voip Drupal uses dialplan scripts to control call flows through actions like playing audio, recording input, and conditional branching. These scripts can be used to build applications such as weather services, surveys, reminders, and community help lines.