(AP) -- On Sept. 11, 2001, as firefighters rushed into the smoldering twin towers, their radios went dead. Police on the scene couldn't hear orders from their superiors. And none of the agencies responding to the nation's deadliest terrorist attack could communicate with one another.
"To this day, I have nightmares of police officers calling for help and not being able to answer them," said Bruce Adler, who was a radio dispatcher that day.
In the years since, New York City emergency agencies have upgraded equipment to adapt to the unforeseen, built in redundancies and increased training. Historically tense relationships among police and firefighters have eased some: The agencies train together and can now talk via radios in an emergency.
But first responders here say it's not good enough and they hope legislation will be passed by the 10th anniversary of Sept. 11 authorizing creation of a national network where police and fire departments around the country can talk to each other and share photos, video and other critical data.
The recommendations from the 9/11 Commission, a panel assigned to diagnose the failures behind the 2001 attack, included the need for a national communication network. "Federal funding of such units should be given high priority by Congress," its report said.
Sept. 11 was a convergence of the worst possible problems in communication technology - a jammed commercial network made cell phone use impossible. Police and firefighter radio networks were not compatible.
But the main problem, the FDNY says, was the damage done to infrastructure called repeaters, which made radio signals work at the twin towers. That left many commanders and firefighters unable to talk to each other. Firefighters in the stairwells couldn't hear the evacuation order and as a result, 343 died.
On the ground, 23 police were killed and 37 Port Authority of New York and New Jersey officers died.
City leaders pledged to fix many of the problems and have done so, starting at the most critical and working down the list - and they continuing to hone skills and refine technology.
For the FDNY, the top priority was to build redundancy into its system so their radios would work no matter what was damaged. They built portable repeaters so walkie-talkies can work through a high-rise building or down into the subway, said Edward Kilduff, chief of department. The FDNY built the use of these tools into their emergency drills.
"We're better-equipped from a technology point of view, from a personal protective equipment point of view and from a communications point of view, and a training point of view," he said.
Though tensions and turf wars still exist, the departments are working better together. Technology was created or modified to allow police helicopters can give information to firefighters on scene. With a click of their radios, FDNY chiefs can contact the NYPD dispatch to start a line of communication on a police frequency. And the departments hold joint drills at high-rise buildings, and in tunnels and prominent locations.
Beyond the city, the NYPD operates a radio frequency on a regional airwave that allows different agencies to communicate in an emergency. But it doesn't go far enough, said Deputy Chief Charles Dowd of the NYPD Communications Division.
For example, when first responders from New York went to help New Orleans after Hurricane Katrina, their radios weren't compatible.
Legislation to pay for a national emergency network is being championed by Democratic senators Jay Rockefeller of West Virginia and Kirsten Gillibrand of New York, and Rep. Peter King, a New York Republican.
And no public safety network right now is strong enough for data sharing.
"Right now, you are able to share more information on your smartphone than any of our first responders," Dowd said. "It doesn't make sense."
The cost has been estimated at $10 billion to $12 billion. Advocates argue it would also benefit rural departments.
Steve McClure, the director of Jackson County Emergency Medical Service in West Virginia, said he has to carry two cell phones to communicate in the hills and valleys of his rural county because the networks aren't strong enough.
"The plan is to have an infrastructure that's resistant to a terrorist attack, but really is also just plain more reliable than commercial networks," he said.
In rural areas, "you don't have the concentration of resources and the concentration of help coming," said Jeff Johnson, former chief of the Tualatin Valley Fire & Rescue in Tigard, Ore. "It's very important that you are getting whoever your neighbors are into a position where they can be helpful."
Waiting is not an option, advocates say.
"The longer we wait, the greater the possibility that we encounter another Katrina, or another terrorist incident where the inability to communicate at all levels is going to hamstring us. In this day and age, to not be able to readily share video and other types of data is ridiculous," Dowd said.
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