An Asterisk VoIP developer specializes in designing, implementing, and managing Voice over IP (VoIP) systems using Asterisk, an open-source framework for building communication applications. They create and configure private branch exchange (PBX) systems for businesses, enabling voice, video, and text communications via IP networks. Their tasks include setting up SIP trunking for external communications, integrating VoIP with existing IT infrastructure, troubleshooting network issues, and ensuring system security. They also tailor the system with custom features like voicemail, call routing, and automated attendants. They need a deep understanding of network protocols, coding, and telecommunication systems.