PETERSON AIR FORCE BASE, Colo. - As the military combatant command charged with defending the American homeland, one of U.S. Northern Command's missions is providing defense support of civil authorities, such as support to state and local first responders, as directed by the president or secretary of defense during a national emergency.

Having Department of Defense personnel and their civilian counterparts working side-by-side at incident scenes means that everyone needs to be able to talk to each other. And that means having compatible communications equipment.

To that end, USNORTHCOM is participating throughout this month in the annual Department of Defense Interoperability Communications Exercise, or DICE. One of USNORTHCOM's subordinate commands, Joint Task Force Civil Support, is hosting part of the exercise at Fort Monroe, Va., while other participants are at Fort Huachuca, Ariz.

"The DICE venue is an opportunity for Department of Defense, National Guard and local first responders to get together to test their communications systems and work with each other to ensure that the systems are interoperable and we can share information between DoD, federal and local responders," said Jim Rizzo, chief of USNORTHCOM's command, control, communications and computers plans section.

DICE participants include personnel and equipment from each of the military services and the Coast Guard, the National Guard, the Department of Homeland Security and state and local agencies.

The seven-week DICE exercise has two main goals, according to Rizzo.

"One is ... Joint Interoperability Test Center certification of military equipment," Rizzo said. "There's also, at the end of the certification period, an exercise on how we communicate so that the local responders and the other folks ... at the venue have an opportunity to get some hands-on experience with interoperating with military forces."

JTF-CS has medium and heavy tactical communications packages undergoing certification at DICE, said Patty Critzer, deputy of the JTF-CS communications systems directorate.

"We're working with the 20-some other units that are out here and actually doing radio checks and communication checks, making sure that we can talk from our command post down to our first responders," Critzer said.

Radios and hardware aren't the only components that need to be compatible at the scene of emergencies. Responders themselves may not communicate clearly due to cultural and language barriers, Rizzo said. But DICE and other exercises build cultural ties and help groups understand a little more about each other's point of view, he added.

"Every time we have an exercise where it affords us the opportunity to start working with the local responders and the local community or the state or the National Guard," Rizzo said, "it breaks those barriers down just a little bit more, so that we can effectively interoperate with each other."