Descriptions:
NetworkChuck walks through a complete build connecting a 3CX VoIP phone system to Claude Code via SIP (Session Initiation Protocol), giving an AI agent a real phone number and enabling voice-driven agentic workflows from anywhere—including analog payphones with no internet connection required. The architecture required solving two non-trivial problems: a SIP server and a separate media server for audio handling, which Chuck resolved using open-source tooling after nearly committing to a $1,000/month commercial stack.
The resulting system supports persistent session context across a call, letting users chain multi-step requests—checking server health, creating ClickUp tasks, sending Slack DMs with direct links—without re-establishing context. A “fire and forget” mode lets users hang up while the agent continues executing long-running tasks like AI thumbnail generation, delivering results asynchronously via Slack. Chuck also creates “Stephanie,” a purpose-built AI receptionist persona for his Ceph storage cluster, defined through system prompts and guardrails inside Claude Code.
The video also demonstrates 3CX’s built-in AI receptionist feature—configured in under 10 seconds with an OpenAI, Google, or local model API key—as a simpler entry point before diving into the custom SIP integration. The full stack is built on 3CX’s free tier, making the phone-to-Claude-Code bridge accessible to anyone running a Linux or macOS machine.
📺 Source: NetworkChuck · Published January 23, 2026
🏷️ Format: Hands On Build
