How to replace Twilio with a local SIP/PBX setup for an AI Voice Bot in Pakistan?

12 hours ago 1
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I have built a voice-to-voice bot using Python (FastAPI) and Twilio. The orchestration logic handles the STT, LLM, and TTS flow. Currently, I am using a Twilio virtual number, and it works fine for testing.

However, I need to deploy this bot for a hospital in Pakistan using a local landline or mobile number (e.g., 051-xxxxxxx or a mobile series). Twilio does not currently offer local inbound numbers for Pakistan that support programmable voice.

Current Stack:

Logic: Python (FastAPI/WebSockets)

AI: Gemini Live / Custom RAG

Telephony: Twilio (Current)

The Problem: I need a "bridge" that can accept a call from a local Pakistani carrier (like PTCL or Nayatel) and pass the audio stream to my Python logic, similar to how Twilio’s Webhooks or Streams work.

What I’ve Looked Into:

SIP Trunks: I am considering getting a SIP Trunk from Nayatel or PTCL.

Asterisk/FreePBX: I understand this can act as a local PBX, but I am unsure how to "stream" the real-time audio from Asterisk to my Python script for low-latency voice-to-voice interaction.

ZIWO: I’ve heard this integrates with Nayatel, but can it be used as a direct replacement for Twilio's Programmable Voice API in this region?

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