A practical, production-ready guide to configuring BSNL SIP PRI (IMS SIP Trunk) on modern Asterisk (PJSIP) with OpenVPN. Covers authentication, routing, user_eq_phone, scoring logic, debugging, and real-world carrier behavior. BSNL now delivers SIP PRI over FTTH fiber using IMS-based SIP signaling routed through VPN (OpenVPN or SoftEther). Key realities: SIP Proxy is reachable only via VPN SIP authentication may use: IMS expects proper user=phone format RTP may traverse different subnets If your PBX doesn’t support OpenVPN natively, you must deploy a router or gateway device that does. 🛠 Step 1 – Configure OpenVPN BSNL provides: VPN Server Primary IP VPN Server Secondary IP Virtual IP (Client) Gateway Mask After connecting: ip addr show tun0 ip route ping 10.x.x.x # SIP Proxy Ensure: VPN interface is UP Route to SIP proxy goes through VPN SIP proxy is reachable 🧩 Step 2 – Configure BSNL SIP Trunk (PJSIP – NOT chan_sip) Modern Asterisk uses PJSIP , not sip.conf. Below is a ...
Imagine a receptionist that never takes a break, speaks 20+ languages, answers 100s of calls a day, and logs every word into your CRM.
That’s the power of a white-label AI Voice Assistant powered by GPT-4, Whisper (STT), Polly/ElevenLabs (TTS), Twilio, GoHighLevel, and n8n.
Over the past few months, I’ve built custom voice bots for clients in real estate, law, med spas, home services, and even Shopify stores — helping them cut costs by 60–80% and automate lead handling, booking, and qualification without losing the human touch.
Here are industry-specific use cases where a voice AI assistant is not just a nice-to-have — it’s a game-changer:
🏢 Real Estate Agents & Brokerages
📞 Use Case: Answer missed calls 24/7, qualify leads, ask budget/zipcode, and book showings. 💸 Impact: Replace part-time reception ($2K+/mo) with a $50–$150/mo AI agent.
🧠 CRM: GoHighLevel tags and triggers can instantly launch workflows.
✅ Self-hosted = ~$60/mo in infra; Cloud-based = ~$100–150/mo.
⚖️ Law Firms
📞 Use Case: Intake call bot that captures case type, urgency, and forwards qualified leads.
💸 Impact: Save $2,000–3,000/month in receptionist costs; never miss a lead after hours.
🧠 Bonus: Secure logs of every call, with transcript and sentiment.
✅ Self-host = lower cost, higher privacy; Cloud = faster launch.
🧖 Med Spas, Clinics & Dental Offices
📞 Use Case: Book appointments, answer FAQs, handle no-show follow-ups via voice.
💸 Impact: Reduce front desk load by 50%, increase rebooking rate.
🧠 Integrated with GoHighLevel appointment calendars + SMS follow-up.
✅ Self-host = ~$50/mo infra; Cloud = ~$120/mo all-in.
🛠️ HVAC / Home Services
📞 Use Case: Capture service address, problem, urgency, and assign to technician queue.
💸 Impact: Automate call triage, boost response time, no call center needed.
🧠 Integration with n8n can dispatch jobs to field team or CRM.
✅ Twilio + GPT + STT/TTS = cheaper than hiring answering service.
🛍️ E-Commerce & Shopify
📞 Use Case: Handle post-purchase inquiries (Where’s my order?), returns, and basic support. 💸 Impact: Reduce customer support calls by 40–70%, improve CSAT.
🧠 Add voice-to-chat options, logs to CRM, or push data into helpdesk tools.
✅ Serverless or webhook-based deployments scale well here.
🤝 Marketing Agencies
📞 Use Case: Resell as a white-label AI phone bot to clients — automate lead calls,
FAQs.
💸 Impact: Add $500–$2,000/month recurring per client.
🧠 Branded dashboard, GHL sync, and n8n automations = high perceived value.
✅ Self-host = higher margin, Cloud = faster delivery.
⚙️ Hosting & Cost Breakdown (Assumptions)
You’re looking at under $150/month for a system that can replace $2K–$5K in staffing, while delivering instant response times, no training required, and 24/7 availability.
🎯 Final Thoughts
AI voice agents are no longer futuristic — they’re practical, affordable, and ready to work for your business today.
Whether you're an agency looking to offer AI services, or a business owner wanting to reclaim hours of lost time — a white-labeled GPT-4-powered voice agent could be the missing piece.
💬 Curious how it could work for your niche? Drop a comment or DM — I’ll walk you through a demo.