Over the last few years, robocalls have quickly grown into one of the most universally despised issues among mobile phone users in the US. The seemingly exponential growth of spam calls has us heading toward a time where a majority of the phone calls made are spam. Today, T-Mobile, Comcast, and telecommunications company Intelliquent are announcing a technical milestone in the war on robocalls — the first call routed across three networks using an end-to-end implementation of the FCC recommended STIR/SHAKEN cryptographic security framework.

After being inundated with complaints regarding the increasing number of spam calls, the FCC issued a ruling to allow network providers to block them by default. Since then, several carriers have implemented measures to do just that.

T-Mobile and Comcast first announced their successful STIR/SHAKEN interoperability back in April — which, according to T-Mobile, was the first time call verification standards functioned between networks. The addition of a third network into the equation may seem minor. Still, it serves as an excellent proof-of-concept for the complexity involved with enforcing call verification across the telecommunications industry. These technical advancements will strengthen T-Mobile's Caller Verified system that displays a "caller verified" message on the incoming call screen if the system verifies the number as legitimate.

As of today's announcement, Caller Verified is available to all T-Mobile customers on 17 different smartphone models, with more on the way.