T-Mobile US and AT&T stepped-up their fight against nuisance calls with the launch of a caller verification scheme which runs across both their networks.

Using their respective implementations of a spam prevention framework known as SHAKEN/STIR, the pair will identify legitimate calls placed between their networks with a verification message on the recipient’s handset. Calls which illegally use fake or spoofed numbers will fail authentication.

A T-Mobile representative told Mobile World Live the service is available to customers using Samsung’s Galaxy Note 8, Note 9, S8 and up, and also LG’s G7 ThinQ, G8 ThinQ and V40 ThinQ. The operator is working with phone manufacturers to deploy the technology on additional devices this year, the representative added.

US residents received nearly 48 billion robocalls in 2018, with scam calls accounting for 17.7 billion of the figure, data from prevention company YouMail showed. It forecast the number to hit between 60 billion and 75 billion in 2019.

In a joint press release, AT&T and T-Mobile acknowledged authentication alone won’t stop automated calls, but called it “a key step toward giving customers greater confidence and control over the calls they answer”. They added the technology will be able to filter more calls as additional operators and device providers implement the standards.

In April, T-Mobile deployed a cross-network verification system with Comcast, a set-up AT&T also reportedly uses.