Scam Code compliance measures by Australian carriers

To combat scam calls and messages, Australia has implemented a revised Scam Code (2022), which outlines requirements for Carriage Service Providers (CSPs). All CSPs are required to cooperate with one another and with government agencies such as the ACMA and ACCC to actively reduce scam traffic across voice (calls) and messaging (SMS).

This article outlines both new and existing measures introduced by major Australian carriers, and how these may impact Aircall customers.

New carrier measures starting July 2025

Optus: IVR challenge for off-net calls

From 31 July 2025, Optus will begin progressively introducing an Interactive Voice Response (IVR) Challenge for calls that:

• Use an Optus Mobile Calling Line Identifier (CLI), and

• Are originated outside the Optus network

How the IVR Challenge works:

• The caller hears:
  “Welcome, to connect your call please enter the following three digits followed by the hash key: xxx.”
  (where xxx is a randomly generated 3-digit code)

• The caller must enter the correct code to proceed

• Up to three attempts are allowed before the call is disconnected

IMPORTANT: Optus has advised that it does not intend to provide broad support for whitelisting to enable carrier redundancy or diversity.

Vodafone: Suspicious call indicator

From 23 July 2025, Vodafone will start flagging suspicious calls on users' handsets. This will apply to calls that:

• Originate outside the Vodafone network, and

• Present a Vodafone Mobile CLI

The handset may display a suspicious call warning, helping recipients identify potentially fraudulent activity.

Previous anti-scam measures

Telstra: IVR challenge for unusual or off-net calls

Since March 2023, Telstra has enforced an IVR challenge for calls that meet any of the following:

• Originate outside the Telstra network

• Use a Telstra A number calling a Telstra B number

• Display unusual calling patterns, even if on-net

To proceed, callers must respond to a digit prompt from the IVR system.

TPG: Blocking of off-net call spoofing

As of August 2023, TPG began blocking calls that:

• Originate outside the TPG network, and

• Use a TPG A number calling a TPG B number

These calls are rejected to prevent misuse of legitimate numbers by scammers.

Impacts on Aircall customers

The rollout of anti-scam measures may affect Aircall users differently based on the number type and network conditions. Below are the most common scenarios:

Recommended solution

If your calls are being affected by these anti-scam measures, porting options are accessible by contacting our Customer Support team.