Expert needed to Integrate 4-Port GSM Gateway with Asterisk/FreePBX for Automated IVR & SMS API

Project Title: ​Expert needed to Integrate 4-Port GSM Gateway with Asterisk/FreePBX for Automated IVR & SMS API ​Project Description: ​"I am looking for a VoIP/Telephony expert to set up a complete automated IVR calling system for my fintech app. ​Hardware & Infrastructure: ​I have a 4-Port GSM Gateway (Dinstar/GoIP or equivalent). ​I have my own Cloud Server (VPS). ​Scope of Work: ​Asterisk/FreePBX Setup: Install and configure Asterisk or FreePBX on my cloud server. ​SIP Trunking: Securely connect my 4-Port GSM Gateway (located at my office) to the Cloud Server via SIP Trunk. ​Automated Calling API: Create an API that my mobile app can trigger to make automated outbound calls (Voice IVR). ​SMS Integration: Enable the ability to send OTPs and automated text messages via the Gateway's SIM cards. ​Call Status & DTMF: The system must report back whether the call was answered and capture any key-press (DTMF) feedback from the user. ​Requirements: ​Previous experience with Asterisk/FreePBX is a must. ​Understanding of SIP, VoIP security, and API integration. ​Knowledge of GSM Gateways and remote configuration."