Most people think of emergency responders using radios like walky-talkies; that is, you talk, and everybody on your freq hears you. It doesn't work this way at all, There may be hundreds of people with com gear and in a big flap everyone is trying to talk at once; what you would get is chaos.

To avoid this confusion, what happens is that every handset is pre- programmed so it can only talk to, and listen to, certain other radios. This is usually accomplished by every unit transmitting to and receiving from a computer controlled central tower or mobile unit somewhere (or several, for backup). Before an emergency, or during an emergency when the situation changes, the lines of communication are specified and people at different levels in the organization get to talk or listen to only certain other people. The signals may also be scrambled for security purposes. A firefighter may report to a supervisor and ask for help, who in turn sends an order to another unit based on that info so it can provide assistance. The first guy does not hear the second talking to the third, and no one else there hears anything he doesn't need to know. Keeping all this straight in the confusion of a real emergency takes a lot of planning and practice and specialized training. It's a management issue, a policies and procedures thing more than it is a technical one.

Now, imagine several different agencies with systems like this (perhaps incompatible!) suddenly having to work together at a big disaster. Add to this units coming in from out of town with different gear manufactured by different vendors. At the local level, say fighting a fire or directing a SWAT unit, the system works pretty well because these guys train all the time. But for the Homeland Security type of emergency, that no one can fully anticipate and really drill for properly, what you often get is a real Chinese fire drill.

Needless to say, a lot of work and study is now going into this problem, and people are trying to retrofit expensive and hard to replace systems with the technical and organizational solutions that will allow them to work together. It ain't easy, especially with inter-agency rivalry and conflict between systems. No on who has spent a fortune and years putting together, debugging and training up a solid and effective system wants to hear he has to start all over from scratch because somebody in Tallahassee or Washington has decided on a new set of standards. Meantime, the vendors are all engaged in fierce competition to see that their gear is selected, and they have every incentive to make it incompatible with everyone else's.

To confuse things even more, you're going to get cases where standardization of procedures and equipment is near-impossible. Communications requirements for fire, police and other missions are often very different, and you're going to have people involved who are on completely different protocols designed for other purposes, like the National Guard, Civil Air Patrol, or the Coast Guard.

It's a big problem the nation is only now starting to come to grips with due to our experience with events like 9/11 and Katrina. Fixing it is going to take time, money, hard work, and a lot of compromises. The problem is a bit more complicated than "the police radios aren't on the same frequency as the firemen's."

It isn't just communications either. How do you organize and set up a command structure to coordinate multiple agencies who may have never worked together before, and who are arriving hapahazardly at the scene of a big incident, like a major terrorist attack? Who's in charge?
What's the chain of command? You need to get this sorted out and drilled before the balloon goes up. I've just finished a set of grueling courses on how this is supposed to all go down, and it meant reading manuals, taking courses, examinations, etc. Just organizing this training on a nationwide level is a colossal job.

The fact that the response to 9/11 went as smoothly as it did, especially since the NYC Emergency Ops Center was taken out when the attack started, is a testament to the skill, dedication and courage of these guys.