City officials said it was the first time the system failed since it was upgraded 18 months ago, but they said alternative plans worked properly and emergency response was not delayed.
For some departments, the solution meant relying on laptops in their vehicles during the down time, while others used cell phones and text pagers. Still, others relied on an old radio system abandoned years ago.
"All of us have redundant systems and back up each other because you can't be without communications," said Matthews Police Capt. Garland Amos.
Motorola engineers spent most of Thursday trying to determine why voice radio communication was lost from 6:51 a.m. until 7:19 a.m. An exact cause had not been determined, but city spokeswoman Julie Hill said three devices failed at the same time.
Hill said two pieces of hardware control the radio system. If one goes does down, the other is supposed to take over. On Thursday morning, both went down and then a backup system also failed.
The system connects 10,000 radio users, mostly from Charlotte-Mecklenburg police, Charlotte Fire Department, North Mecklenburg Volunteer Rescue Squad, Matthews-Mint Hill police departments, Medic and the Mecklenburg Sheriff's Office.
That meant that when someone called 911, dispatchers could receive the call but they couldn't radio to the officers or firefighters who needed to address the problem, Hill said. Instead, they had to rely on cell phones, laptops, pagers and landlines to alert agencies about the emergency.
Then each agency had its own backup plan for communicating with its employees.
Charlotte-Mecklenburg police used computers in each patrol car to dispatch officers to calls, tell them about the failure and give them instructions on what to do, said spokesman Keith Bridges.
The Charlotte Fire Department alerted its stations to have someone stand by the phone, said Fire Chief Luther Fincher, who was in his office when the system crashed. Firefighters could also communicate through data terminals in their fire trucks, he said.
Medic used digital pagers to tell paramedics where they needed to go and what problem the person there was having. The paramedics used a mobile data system on their ambulances to tell communications workers when they arrived, when they left and whether they were taking a patient to a hospital.
Meanwhile, the Matthews and Mint Hill police departments just switched their radios to an old frequency and used an old system from about eight years ago, said Matthews Police Capt. Garland Amos.
Charlotte-Mecklenburg police officials are hoping to upgrade their communication system by the end of next summer to improve transmissions among 11 counties around the region. A $6 million federal grant, plus $2 million from the city of Charlotte would allow agencies to communicate beyond county lines in the event of a disaster.
But first they need to figure out a way to prevent problems like Thursday's failure.
Communications workers and the system's engineers realized Thursday's problem about the same time.
Hill said the city has used the Motorola system since 1988 and it underwent a major upgrade about 18 months ago.
Engineers were expected to replace the parts late Thursday and then take the old hardware back to their lab to try to determine what went wrong, Hill said. The engineers told her it was the first time the Motorola system had ever failed.
