Tech Tweak

A Texas grocery store turned police station presented technological challenges.

by / January 30, 2006
About five years ago, the Flower Mound, Texas, Police Department moved into its new digs -- a renovated grocery store.

To construct a new building or move into a newer one would cost money the department didn't have, so the grocery store became the department's new home. Officers soon discovered a problem: The building's roof was largely renovated with 2-inch steel, which made communicating via handheld radios on the 800 MHz radio system less than stellar.

"Big, giant steel roofs and handheld radios don't mix. The signal is dead,"said Capt. Byron Lake of the Flower Mound Police Department.

The police department explored various options, including mounting an internal antenna to bypass the steel roof. But any option would have been too expensive, like the $200,000 it would have cost for that internal antenna. The police department turned to the Flower Mound Department of Information Services, and its director, Dustin Malcom, for help.

"We began looking at a way to, instead of having them using their handhelds while they're in the station, use their computers to listen and respond to calls while inside the station," Malcom said.

Successful Experiment
Two years of experimentation and tweaking voice-conferencing software resulted in a solution that bypasses the radios, and allows officers to monitor radio and TV transmissions through a computer. "Essentially we are voice conferencing with different analog radio devices," Malcom said. "Ordinarily you'd voice conference with a person, but we've altered the way the voice-conference software works and the way the analog system works, and made it so that you actually conference with a radio, TV or handheld radio -- or anything that's an analog audio signal."

This means the 67 officers on the force can listen to everything that goes out over the 800 MHz radio system and respond to calls from dispatch by listening to the computer. They can also tap into CNN, MSNBC or the local television station, TXCN.

"If we have a regional or national incident, they can have constant radio feeds to their computer no matter where they are, so they don't have to go to a TV, they don't have to go to a radio, it's already coming over their computer," Malcom said. "You may have one officer listening to TXCN or another officer listening to CNN."

And Lake said officers don't lose connectivity with what's going on. "Any officer can be sitting at a station in the building, working on reports and whatever they're doing, and picking (the signal) up off their computers," he said. "I can be sitting at home, pull up my laptop, click on and monitor all the radio traffic off my computer."

Malcom began the process by simply finding a way to use handhelds effectively in the station, but began to uncover other possibilities along the way. "Once we figured out how to do that, it opened up all the doors we didn't realize we were about to open, with the ability to actually conference a variety of different radio sources -- either national or local."

The project is still in testing, and it will be a long time before that phase is finished. Once it is, however, Malcom envisions a system whereby officers can listen to radio reports from a variety of sources, and also communicate with one another via the computer. "That's the part that's still in testing. There are a lot of tweaks going on there as well, but that's the part that's so revolutionary -- that you can, using a computer, talk to somebody in the field who's on a radio."

Lake said the long-term plan is to extend the capability to each squad car as a radio system backup. "In the field, we hope it's going to help us in low-lying areas where we lose connection with the radio tower, and the cellular towers will take that information up and transfer it over the Internet."

The Device
Malcom said he developed a device out of "duct tape and a soldering iron" that merges the city's sole analog radio system with one of six desktop computers that form the police department's communications hub. Each PC is dedicated to a particular audio signal, and one PC handles audio from the city's radio system.

Malcom attached the device, really a modified Motorola VoiceDucer microphone, to the PC handling the audio for the radio system. He then installed voice-conferencing software on the same PC.

"I rewired the [VoiceDucer] device to think that when it receives a signal from the computer associated with the radio system, the microphone interprets that signal as a person speaking and then opens the voice channel on the radio system," he said.

Malcom said the VoiceDucer is designed to pass the voice of a person talking. By rewiring it, he "tricked" it into responding to an electrical pulse put out by the computer it's attached to in the hub instead of responding to a person's voice. That way, users in the building can tap into the voice-conferencing software to access audio channels they're interested in.

Staff members authorized to speak to law enforcement personnel over the radio system use the voice-conferencing software on their PCs to select the appropriate outgoing audio channel and open communications with officers on the radio system via a headset microphone. All that's needed to run the system is one modified VoiceDucer device, a computer and an Internet connection.

"You only need one device for the system," he said. "One does it all, and it's located in our central office where all the equipment is stored. I haven't seen anything that would limit the number of users on the system."

The system could benefit the department in a few ways. First, officers won't have to carry a handheld radio to listen for calls or news while at the station, cutting down on radios needed and saving the department $2,500 for each base model. Second, as more patrol cars are equipped with laptops, the computers could offer an additional form of communication between officers in the field.

Malcom said he doesn't know how much the patent-pending device would cost to produce, and he doesn't plan on selling it to individual agencies. "Didn't cost me anything to do it," he said. "Flower Mound doesn't plan on selling this item directly, but we're open to some company buying it, and mass producing it."

The system solved the communications problem within the Flower Mound Police Department, and can potentially back up the 800 MHz radio system in the field -- but it's too early to see it as a total replacement for the radio system, Lake said. "So far, it doesn't have the clarity or flexibility of the radio," he said. "How do you carry a computer everywhere you go versus a handheld radio? Also, will computers in the long run really have the durability and reliability that a car radio has?"
Jim McKay, Justice and Public Safety Editor Justice and Public Safety Editor