Every missed call is a missed lead. For a repair shop that lives and dies by walk-ins and phone calls, letting a call go to voicemail without any follow-up is just leaving money on the table.
Here's how I built a missed call text-back system using Asterisk AMI events and a Node.js worker. When a call hits the queue and nobody answers, the caller gets an SMS within seconds.
The Stack
Asterisk AMI for call events, Node.js for the listener, Twilio (or any SMS provider with a REST API) for outbound texts. MySQL to log everything so you can track response rates.
How It Works
The AMI listener watches for Hangup events where DialStatus is NOANSWER or BUSY. When one fires, it checks the caller ID against a simple opt-out list, then fires an SMS via the provider API.
The whole thing runs as a PM2 process alongside FreePBX and adds zero load to the system.