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 ...
In today’s hyperconnected world, communication is no longer just about voice. Businesses demand seamless, scalable, and intelligent communication platforms that unify voice, video, chat, and data all driven by APIs and automation.
That’s where UnifiedPBX steps in a next-generation Telephony Platform-as-a-Service (TPaaS) that powers both Contact Center as a Service (CCaaS) and Unified Communications as a Service (UCaaS) offerings.
Built on a microservices architecture with deep API integration and modern DevOps principles, UnifiedPBX brings together the best of Asterisk and FreeSWITCH to deliver enterprise-grade communication at cloud speed.
🌐 Why UnifiedPBX?
At its core, UnifiedPBX isn’t just another hosted PBX. It’s a developer-friendly telephony platform designed to help telecom operators, call centers, and enterprises build their own branded CCaaS and UCaaS solutions with modular APIs, scalable infrastructure, and full WebRTC support.
Imagine having the power to manage every aspect of your telephony stack from call routing and IVRs to live dashboards, agent performance, and real-time analytics all through APIs and intuitive dashboards.
🎯 Core Capabilities
💼 Contact Center Features (CCaaS)
UnifiedPBX redefines how customer engagement works by offering a fully modular and data-driven contact center suite:
- Agent Management – Complete agent lifecycle, skill-based routing, and live presence tracking.
- Campaign Management – Automated outbound campaigns with lead segmentation and dynamic assignment.
- Queue Management – Advanced ACD logic, priority queues, overflow handling, and callback scheduling.
- Dynamic Call Scripts – Create flexible call flows with variable interpolation and real-time data integration.
- Live Monitoring – Real-time dashboards for supervisors to track agent KPIs and call status.
- Call Recording – Secure recording, storage, and playback for compliance and training.
- IVR System – Multi-level IVR with database lookups, custom flows, and language prompts.
- Omnichannel (Planned) – Unified inbox for voice, chat, and email to simplify customer interactions.
☎️ Unified Communications (UCaaS)
Empower teams with powerful collaboration and communication tools:
- Enterprise IP PBX – Robust internal telephony system supporting extensions, call transfer, and call parking.
- SIP Trunking – Flexible connectivity with failover and redundancy options.
- Conference Calling – Secure, multi-party conferencing with PIN-protected access.
- Voicemail System – Visual voicemail, voicemail-to-email, and transcription-ready.
- Presence & Status – Real-time availability updates for smarter routing.
- Mobile Softphones – WebRTC and mobile app support for remote teams.
⚙️ Under the Hood: Modern Technical Architecture
UnifiedPBX is engineered with modern distributed systems principles ensuring resilience, scalability, and developer agility.
🧩 Architecture Overview
- Dual Telephony Backends – Switch seamlessly between Asterisk (AMI/ARI) and FreeSWITCH (ESL).
- Microservices Design – Seven independent services, each with dedicated REST APIs.
- Real-Time Communication – WebSocket-powered live updates for call status and analytics.
- Role-Based Access Control (RBAC) – Admin, Agent, and Customer roles with fine-grained permissions.
- WebRTC Integration – Browser-based calling using SIP.js.
- Configuration Automation – Dynamic generation of Asterisk/FreeSWITCH config files.
- Backup & Recovery – Automated snapshots and point-in-time recovery for business continuity.
- Dockerized Deployment – Containerized services ready for orchestration.
💻 Frontend Experience
The front-end experience is designed for speed, accessibility, and usability enabling admins, supervisors, and agents to operate efficiently.
🖥️ Key UI Highlights
- React 18+ PWA Dashboard – Responsive, fast, and installable web app.
- State Management – Context API and React Hooks for predictable UX.
- Real-time WebSocket Feeds – Instant call and agent updates.
- Accessibility First – WCAG 2.1 AA compliance.
- Offline Support – Progressive Web App powered by Workbox.
- Modern Styling – Built with Bootstrap 5 and Tailwind CSS.
📊 Analytics, Metrics, and Monitoring
UnifiedPBX gives deep insights into both system and business performance.
- Call Detail Records (CDR) – Comprehensive call logs with filters and BI-ready data.
- Application Metrics – Track latency, API performance, and error rates.
- System Metrics – CPU, memory, and I/O monitoring.
- Business KPIs – Call volumes, campaign results, and agent productivity.
- Logging Strategy – Centralized JSON logs with rotation, aggregation, and monitoring.
☁️ Scalability & DevOps Excellence
Built for high availability and horizontal scalability:
- Load Balancing – Nginx reverse proxy with sticky sessions.
- Database Scaling – PostgreSQL read replicas and connection pooling.
- Caching Layer – Redis cluster for performance acceleration.
- Service Scaling – Container orchestration ready (Kubernetes/Docker Compose).
- Monitoring & Alerts – Health checks, uptime metrics, and automated notifications.
🔐 Security and Reliability
Security is baked in at every layer:
- JWT Authentication with refresh tokens.
- SSL/TLS Encryption with Let’s Encrypt automation.
- API Versioning and standardized REST design.
- Audit Logs for every sensitive operation.
🌍 Developer-First. Enterprise-Ready. Future-Proof.
UnifiedPBX is built for businesses that demand control, flexibility, and innovation. Whether you’re launching your own cloud contact center, building telephony-enabled SaaS products, or modernizing enterprise voice systems, UnifiedPBX gives you the tools, APIs, and scalability to make it happen.
🚀 The Road Ahead
With upcoming integrations for:
- Omnichannel Messaging (WhatsApp, Web Chat, Email)
- AI Voice Bots & Transcription
- Advanced Reporting Dashboards
- Multi-Tenant Management Portal
UnifiedPBX is not just keeping pace with the telecom industry it’s setting the standard.
💡 In Summary
UnifiedPBX is more than an IP PBX it’s a complete Telephony Platform-as-a-Service designed for the cloud era. API-driven. Modular. Scalable. Secure.
If your business relies on communication UnifiedPBX can power it.