Learning from experience

The 1999 incident at Columbine High School represented numerous failures for the Denver area, not the least of which was a lack of interoperable communications during emergencies. Since then, the city has been searching for a better way for its first responders to talk with each other without help from a dispatcher or changing radio systems.

In 2003, the city formed a Communications Committee to review the area’s communications systems. Using the Department of Homeland Security grants, the city replaced or upgraded many systems to improve each agency’s daily operations. Interoperability between those communications systems, however, still was lacking, so the city created a plan to address it in 2003.

First, the city identified a variety of problems from past incidents, including those at Columbine. The research showed that Denver’s first responders were hampered by disparate radio systems and a lack of user training. The city also did not know which systems could talk to each other through a patch, such as an Audio Control Unit (ACU) or other interoperable devices.

Next, the city inventoried the ACUs in the area and discovered that five already were deployed. An ACU either can be fixed at a location, usually a 911 center, or placed in a vehicle. However, all the ACUs required set-up time, which meant that when a police officer or fire fighter talked with someone on a different radio system, the dispatchers — the city’s, as well as the other agency’s — had to create the patch. Denver’s ACU worked well when there was time to wait or during a pre-planned event, but set-up could take up to 45 minutes, which was unacceptable during an emergency.

To connect the city’s VHF, UHF and 800-MHz radio systems at the network level, Denver’s Communications Committee tested NetworkFirst by Lowell, Mass.-based M/A-COM for eight months. Capable of more than 200 concurrent conversations, the system does not require a patch because the audio is converted to Voice over Internet Protocol and sent through a gateway. However, users have to be within the coverage area to use the system. For example, the system will not work in the remote mountains of Colorado, where most public safety radios are inoperable. Also, users on some busier systems with limited frequencies will not get a response until a frequency is available.

Last summer, Denver began working with first responders in the surrounding area to determine their needs. Based on those discussions, the city developed talk groups. Because the first responders wanted a system that was easy to learn and use, the groups were color coded to correspond with different user groups and geographic locations. The blue group represents police, red is the color for fire and medical responders, and gold indicates command and control channels. The Denver metro area was divided into four separate quadrants, using the major interstate routes to divide the region. As a result, a first responder only needs to know which color group to switch to and in which regional quadrant the group is located.

Now, the city is connecting its 911 centers to the interoperability network. The city’s conventional channel for 911 service is frequently over-loaded, but the new system creates a point-to-point talk group that immediately connects all communication centers. As a result, the city can issue Amber Alerts, tornado warnings or a highway closure to all the dispatchers in the area simultaneously.

Using the new system, Denver is communicating instantly with some of its neighbors in surrounding counties. Federal agencies also have been hooked into the system. Although 90 percent of the system’s installation is complete, testing, training and re-training all users is the biggest obstacle to full deployment.
— Dana Hansen is superintendent of radio communications for the city and county of Denver Technology Services.