Outbound Call Automation for Incident Alerting in Brazil using Azure Communication Services (ACS) – Alternatives & Workarounds

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Outbound Call Automation for Incident Alerting in Brazil using Azure Communication Services (ACS) – Alternatives & Workarounds

Fernanda Cosme Oliveira Lima 20

Hi everyone,

We are designing an automated incident alerting system for our DevOps environment. The objective is to trigger an automated outbound voice call (using Text-to-Speech) to on-call developers' cell phones whenever a critical CI/CD pipeline fails.

Our Current Challenge:

Requirement: Automated outbound PSTN calls to mobile numbers in Brazil (BR) via ACS Call Automation API.
Microsoft Response: Upon submitting a support ticket to acquire phone numbers in Brazil, Microsoft support (María) informed us that only Toll-Free numbers are supported for ACS in Brazil, and local/geographic outbound numbers are currently unavailable through Microsoft Calling Plans.

Questions for the Community:

Has anyone successfully implemented outbound call automation to mobile numbers in Brazil using ACS?
Are there alternative Azure-native architectures or third-party integrations that handle outbound alerting calls to Brazilian mobile carriers seamlessly?

Any insights, architecture suggestions, or experiences with ACS in the LATAM/Brazil region would be greatly appreciated!

Thanks in advance,

Fernanda

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Hello @Fernanda Cosme Oliveira Lima

The limitation Microsoft Support gave you matches the current ACS documentation. For Brazil, Microsoft-provided ACS toll-free numbers are currently listed for inbound calling, but not for making outbound calls. So an ACS number obtained through Microsoft Calling Plans isn’t currently a suitable source number for your automated outbound incident calls to Brazilian mobiles.

The most practical ACS-based workaround is Azure Communication Services Direct Routing. ACS supports connecting your own telephony carrier through a certified Session Border Controller (SBC). Your architecture could therefore be:

CI/CD failure → Azure Function/Logic App → ACS Call Automation → ACS Direct Routing → SBC → Brazilian PSTN carrier → Developer mobile

Call Automation can still handle the application logic and Text-to-Speech, while the Brazilian carrier provides the PSTN termination. Microsoft specifically positions Direct Routing for situations where Microsoft PSTN calling isn't available or where you need to retain/use your own carrier.

You would configure ACS voice-routing rules so calls to Brazilian numbers (+55...) are routed through the SBC rather than Microsoft's PSTN infrastructure. ACS supports routing outbound calls to specific SBCs based on the dialed-number pattern.

If deploying and maintaining an SBC isn't desirable, another option is to use a third-party CPaaS/telephony provider that supports programmable outbound calling in Brazil and trigger it from your Azure Function or Logic App. In that case, ACS wouldn't need to handle the PSTN portion.

So, for your two questions:

ACS + Microsoft Calling Plans: I wouldn't design the solution around this today for outbound calls originating from a Brazilian ACS number, given the documented capability limitation.
Recommended Azure architecture: Keep the alerting/orchestration in Azure and use ACS Call Automation + Direct Routing + a Brazilian carrier/SBC if you want to retain ACS. Otherwise, use an external programmable voice provider for the calling component.

Sharing these references with you:

ACS phone number management for Brazil

ACS Direct Routing documentation

ACS PSTN integration and Direct Routing options

ACS Call Automation overview

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