Telco Provider Integration for Microsoft Communication Service

Hi @Isuru Akalanka
Thanks for the question and using MS Q&A platform.
Azure Communication Service's (ACS) capabilities regarding phone number integration and PSTN support.

For phone number integration, Azure Communication Service offers several options:

PSTN Direct Access: Azure has a custody over its owned telecommunication carriers, and through them, it provides direct calling. However, this is not available for all countries. Operator Connect: This is integration with any of their chosen telecom operators, but in limited areas and partners.
Direct Routing: Similar to Microsoft Teams Direct Routing, this allows you to connect your existing PSTN carrier or telecom provider to Azure Communication Services through Session Border Controllers (SBCs).

Regarding Sri Lanka specifically: As of my last update, Sri Lanka is not listed among the countries where Azure Communication Service provides direct PSTN services. However, you have two potential options:

1. Use Direct Routing to connect your local Sri Lankan telco provider through an SBC https://zcusa.951200.xyz/en-us/azure/communication-services/concepts/telephony/direct-routing-infrastructure
   Use direct routing to connect existing telephony service | Microsoft Learn
2. Work with a global telecom provider that has presence in Sri Lanka and supports Azure Communication Service integration

country/regional availability of telephone numbers and subscription eligibility:

Country/regional availability of telephone numbers and subscription eligibility - An Azure Communication Services concept document | Microsoft Learn

Phone number types in Azure Communication Services

Number types

Telephony concepts/Telephony integration

Call Automation Overview