T-Mobile and AT&T work together to fight robocalls across their networks

If there’s one thing most people can agree on it’s their distaste for receiving robocalls. Even T-Mobile and AT&T have decided to put aside their differences and work together to eliminate these loathsome calls.

Today, T-Mobile and AT&T said they are delivering STIR/SHAKEN caller authentication technology that works across both their networks.

The STIR/SHAKEN protocols were developed by industry groups ATIS and SIP Forum. The protocols use digital certificates to ensure the incoming phone number is originating from a device that is registered to that number. A call that is illegally “spoofed” will fail the STIR/SHAKEN Caller ID verification and will not be marked as verified. Conversely, verification will confirm that a call is really coming from the identified number.

Service providers own the telephone numbers that are associated with their networks. But they need to work together to verify a number when the caller and the receiver are using different networks. Both T-Mobile and AT&T have previously announced agreements to work with Comcast.

More calls will be verified over time as more device providers participate and as more network providers implement the standards. While STIR/SHAKEN authentication won’t solve the problem of unwanted robocalls by itself, it is a key step in the fight against robocalls.

In June the Federal Communications Commission (FCC) voted unanimously to give telcos the authority to identify and block robocalls without having to first get permission from subscribers. The FCC said it received 232,000 complaints about unwanted calls in 2018. In an FCC meeting, Chairman Ajit Pai called the automated unsolicited calls "the scourge of civilization."

RELATED: AT&T becomes first carrier to block robocalls by default

A few weeks after the FCC vote, AT&T said it would add automatic robocall-blocking technology to its customers’ accounts, and it said it wouldn’t charge its customers for the service.

But FCC Commissioner Geoffrey Starks has complained that a lot of carriers are dragging their feet in implementing robocall blocking services. “Despite historically clamoring for new tools, it does not appear that all providers have acted with haste to deploy opt-out robocall blocking services,” he said in a statement.