The two carriers announced today that they're rolling out cross-network call authentication. Using the SHAKEN and STIR technologies, incoming calls will be marked as verified if it's confirmed that they're coming from the person that they say they are. This helps to fight robocalls and scammers who spoof calls using techniques like matching the area code and 3-digit prefix of the person they're calling.
AT&T says that it's working on a way to make the SHAKEN/STIR standards work for everyone at no extra cost by making them work with its free AT&T Call Protect service.
Meanwhile, T-Mobile uses SHAKEN and STIR in its Caller Verified service, which is also available on Metro by T-Mobile and works on 12 phones: Samsung Galaxy S10, Galaxy S10+, Galaxy S10e, Galaxy S9, Galaxy S9+, Galaxy S8, Galaxy S8+, Galaxy Note 8, Galaxy Note 9, LG G8 ThinQ, LG G7, and LG V40.
Robocalls can be annoying at best, and so it's good to see AT&T and T-Mobile working together to make things better for their customers.