This article explains how Alphanumeric Sender ID registration works across ACMA and Sinch Engage, and what must happen before registrations can be submitted in the Sinch Engage platform.
Quick summary
Alphanumeric Sender ID registration involves both ACMA and Sinch Engage and works across two systems:
Your Authorized Business Representative (ABR contact) sets up ACMA Assist.
The ABR contact can approve Sender ID registrations themselves or delegate approval to an authorized ACMA Assist user.
Alphanumeric Sender IDs are submitted in the Sinch Engage platform and must be approved in ACMA Assist before they can be used.
Note: You can submit an Alphanumeric Sender ID in the Sinch Engage platform before ACMA Assist is set up. However, the Sender ID cannot be used until ACMA Assist has been set up and the registration has been approved.
Who this applies to
This guide applies to Australian businesses that send messages using branded Alphanumeric Sender IDs.
Key roles (important)
Authorized Business Representative (ABR contact)
The ABR contact is the person who manages the business’s ABN. Only the ABR contact can initially set up ACMA Assist.
Authorized ACMA Assist user
An authorized ACMA Assist user is someone the ABR has approved (or delegated to) to approve Sender ID registrations. This may be:
The ABR themselves, or
Another person in the business (for example, a Sinch Engage platform user).
Step 1: ABR sets up ACMA Assist (required)
This step must be completed by the Authorized Business Representative (ABR contact).
What this step does
It enables Sender ID registrations to be approved. Until this step is completed, no Sender IDs can be registered.
What you need before you start
The MyID app, with identity verified to Standard level
Access to the business ABN
👉 Set up MyID (Standard identity level) How to set up myID
How to complete this step
Follow ACMA’s official guide for businesses and organization's. It covers:
Logging in to ACMA Assist
Adding your ABN
Approving Sender ID registrations
Delegating approval to another authorized ACMA Assist user (optional)
👉 ACMA Assist setup and delegation guide SMS Sender ID Register – User guide for businesses and organization's | ACMA
Step 2: Submit Alphanumeric Sender IDs (Sinch Engage platform)
Once ACMA Assist is set up:
Log in to the Sinch Engage platform
Go to Settings → Numbers
Scroll to Alphanumeric Sender IDs
Select Add new Alphanumeric Sender ID
Submit your registration
Sinch Engage will lodge the application with ACMA on your behalf.
Step 3: Approve the registration in ACMA Assist
After submission:
ACMA will notify the authorized ACMA Assist user
The authorized user must log in to ACMA Assist and approve the request
Until this approval is completed, the Sender ID will not be registered.
If you’re blocked
I’m not the ABR - what should I do?
Identify who manages your ABN and direct them to Step 1 of this guide. They must complete the ACMA Assist setup before anything else can happen.
Can the ABR contact delegate approvals?
Yes. The ABR can delegate approval rights to another authorized ACMA Assist user. Instructions for approving or delegating access are covered in ACMA’s official user guide: SMS Sender ID Register – User guide for businesses and organization's | ACMA
What happens if I don’t register?
From 1 July 2026, unregistered Alphanumeric Sender IDs will appear as Unverified in messages sent to recipients.
Need help?
If you’re unsure who your ABR contact is, or need help with any step, contact Sinch Engage Support or your Account Manager.