Australia AS/CA S042 Standards: 2025 Update & AusAlert
- Aug 14
- 4 min read
Australia Revises the AS/CA S042 Air Interface Standards and Renames NMS to AusAlert
Australia has refreshed the core air interface standards that govern addressable customer equipment connecting to its mobile and satellite networks. In June 2025 the industry standards body issued 2025 editions of AS/CA S042 Parts 1, 4 and 5, superseding the 2022 editions. One year later, in June 2026, it added Amendment No. 1/2026 to Part 1, renaming the National Messaging System (NMS) as AusAlert throughout the document. For manufacturers, importers and test labs, these are not spectrum or allocation changes they are revisions to the type approval baseline that customer equipment must meet to reach the Australian market.
An important framing point sits underneath this update. The AS/CA S042 series is developed by an industry body, not a government regulator. The standards acquire mandatory legal effect only because the Australian Communications and Media Authority (ACMA) references them in its technical standards and labelling instruments. Understanding that split industry standard versus regulatory mandate is essential to reading the compliance implications correctly.
What changed in the Australia AS/CA S042 standards
On 30 June 2025, three revised air interface standards were published, each superseding its 2022 predecessor:
AS/CA S042.1:2025 — Part 1: General. General requirements for addressable customer equipment (CE) intended for connection to a public mobile telecommunications service (PMTS) and/or a satellite service. Supersedes AS/CA S042.1:2022.
AS/CA S042.4:2025 — Part 4: IMT-2000 and IMT Advanced Customer Equipment. Requirements for 3G/4G class CE. Supersedes AS/CA S042.4:2022.
AS/CA S042.5:2025 — Part 5: IMT-2020 Customer Equipment. Requirements for 5G class CE. Supersedes AS/CA S042.5:2022.
On 26 June 2026 (approved 25 June 2026), Amendment No. 1/2026 to AS/CA S042.1:2025 was published and consolidated into the standard. Its substantive effect is a terminology change: the National Messaging System (NMS) is renamed "AusAlert" throughout Part 1, aligning the standard with the public branding of Australia's national emergency cell-broadcast/alerting arrangement.
The AS/CA S042 series applies to addressable CE devices individually identifiable on the network. It does not apply to non addressable equipment such as standalone GPS terminals and satellite navigation systems.
What this means for manufacturers
For suppliers of mobile, 5G and satellite capable customer equipment, three practical consequences follow.
The type approval baseline has moved. Australian market access for addressable CE runs through the Regulatory Compliance Mark (RCM) and a supplier declaration of conformity supported by evidence against the mandated air interface standards. With the 2025 editions superseding the 2022 editions, conformity evidence and declarations should reference the current editions rather than the retired ones. Test reports and design documentation built against the 2022 editions may need re mapping or delta assessment where clause requirements have changed.
The AusAlert rename is administrative, but it touches documentation. Renaming NMS to AusAlert does not, in itself, impose a new engineering test in the way a changed limit or method would. However, declarations, internal test plans, compliance folders and any user facing references that name the "National Messaging System" should be updated to "AusAlert" to remain consistent with the consolidated AS/CA S042.1:2025 wording. Devices implementing emergency alert message handling should be checked against the current Part 1 wording for any consequential clause changes beyond the name itself.
The mandate flows from ACMA, not the ATA. The AS/CA S042 standards become binding through the ACMA Telecommunications (Mobile Equipment Air Interface) Technical Standard 2022 and the associated Telecommunications Labelling Notice. Suppliers should therefore confirm the current mandated edition on ACMA's technical standards page before finalising a declaration the industry standard's publication date and the date it becomes the mandated baseline are governed by ACMA's 12-month transition mechanism, not by the ATA alone.
Scope and equipment coverage
The three parts together define the air interface conformity envelope for network-connected consumer and IoT devices:
Handsets and cellular tablets (smartphones, feature phones, cellular enabled tablets and wearables) Parts 1, 4 and/or 5 depending on radio generation.
5G customer equipment Part 5 (IMT-2020), read with Part 1.
3G/4G customer equipment Part 4 (IMT-2000 / IMT-Advanced), read with Part 1.
Satellite-service addressable CE Part 1 general requirements apply where the device is addressable on a satellite service.
Because Part 1 carries the general and emergency calling requirements (including the alerting terminology now labelled AusAlert), it is read in conjunction with Parts 4 and 5 rather than in isolation.
Certification impact summary
Standard (2025 edition) | Equipment covered | Supersedes | Certification impact |
AS/CA S042.1:2025 (Part 1: General) + Amendment No. 1/2026 | Addressable CE for PMTS and/or satellite service; general and emergency-calling requirements | AS/CA S042.1:2022 | Update conformity references to the 2025 edition; update NMS → AusAlert terminology in declarations, test plans and compliance files; re-check emergency-alert clauses |
AS/CA S042.4:2025 (Part 4: IMT-2000 / IMT-Advanced) | 3G/4G addressable customer equipment | AS/CA S042.4:2022 | Re reference conformity evidence to the 2025 edition; delta assess against any changed clauses |
AS/CA S042.5:2025 (Part 5: IMT-2020) | 5G addressable customer equipment | AS/CA S042.5:2022 | Re-reference conformity evidence to the 2025 edition; delta-assess against any changed clauses |
ACMA mandate instrument | All of the above (legal force) | — | Confirm current mandated edition and applicable transition on the ACMA technical standards page before declaring conformity |
Timeline and required actions
Date | Event | Required action for suppliers |
30 Jun 2025 | Communications Alliance publishes AS/CA S042.1/4/5:2025, superseding the 2022 editions; 12 month transition begins | Begin mapping existing 2022 based evidence to the 2025 editions; scope any delta testing |
24 Jul 2025 | Communications Alliance rebrands as the Australian Telecommunications Alliance (ATA); AMTA folded in | Update supplier records and references to the standards body's current name |
25–26 Jun 2026 | Amendment No. 1/2026 to AS/CA S042.1:2025 approved and published; NMS renamed AusAlert | Update NMS → AusAlert wording in declarations, test plans and compliance documentation |
30 Jun 2026 | 12-month transition from the 2025 publication reaches its nominal end | Ensure new declarations and market entries reference the current mandated edition |
Ongoing | Separate ACMA equipment-rules consultation on emergency calling and grandfathering (covered in prior GMA Labs analysis) | Monitor for a shift in the mandated emergency calling baseline; audit models relying on grandfathering |
