AT&T (T) and T-Mobile are going the extra mile to help their customers in New York and New Jersey stay in touch with one another in the wake of Hurricane Sandy. The two carriers on Wednesday said that they were opening up their networks to each others’ customers in the two states hit hardest by the hurricane and are offering them free roaming. The companies say that “customers will be able to place calls just as they normally would, but their calls will be carried by whichever network is most operational in their area.” AT&T and T-Mobile can deliver seamless interoperability with one another since both use the same GSM and UMTS-based wireless standards for their voice and data networks. The companies’ press release is posted below.

AT&T and T-Mobile Open Networks to Customers of Both Carriers in New York and New Jersey

Dallas and Bellevue, Wash. — October 31, 2012 — In the wake of destruction caused by Hurricane Sandy, AT&T and T-Mobile are taking extraordinary measures to make sure our customers can stay in touch.

AT&T and T-Mobile have entered into an agreement to enable roaming on their networks to customers of both companies in the heavily impacted areas and where capacity is available and for subscribers with a compatible device.

AT&T and T-Mobile customers will be able to place calls just as they normally would, but their calls will be carried by whichever network is most operational in their area. This will be seamless for AT&T and T-Mobile customers with no change to their current rate plans or service agreements even if the phone indicates the device is attached to the other carrier’s network.

T-Mobile and AT&T both utilize network technology based on GSM and UMTS standards, which allows for this sharing of voice and data traffic.