Radio Interoperability In a Box

August 2004
By James Careless

Law enforcement and emergency personnel use the Incident Commanders Radio Interface to link disparate radio systems.
Manportable system allows emergency personnel with disparate communications systems to connect.

First responders from a number of organizations are now equipped with technology that allows them to coordinate their actions in an emergency using an interface that facilitates communications between incompatible devices. The interface enables one telephone and five different radio networks to interconnect by plugging in a telephone or radio handset from each network. The small, lightweight unit has been tested by the U.S. Air Force and currently is in use by the National Guard and several law enforcement groups.

The Incident Commanders Radio Interface (ICRI) allows a rapid communications link among military, state and local first responders. The unit, which weighs 3.5 pounds, links the radios and telephone using cables connected to each unit’s speaker and microphone ports. The interface does not include a microcomputer nor any interface to allow an outboard laptop to run the device. However, an ICRI is available that can divide the attached radios/telephone into two separate talk groups. To assign a radio to either talk group A or B, the user flips an A/B toggle switch on the ICRI device. One switch is provided for each input.

The unit is completely manportable, says Sgt. 1st Class Curtis Stapleton, a member of the Oklahoma National Guard’s 63rd Weapons of Mass Destruction–Civil Support Team (WMD-CST). “It runs off an external power pack containing eight AA batteries and is so small and light that you can carry it in your rucksack,” he explains.

The ICRI can operate on power from an onboard AA battery pack, from a direct connection to a patrol car’s cigarette lighter or from an alternating current (AC) adapter plugged into house current. This feature is particularly important to the Hagerstown, Maryland, Police Department (HMPD), whose Joint City-County Special Response SWAT team relies on the ICRI during hostage incidents. “Say we’re inside a school, and we are using the ICRI to provide radio communications to officers in the basement,” explains Capt. Charles Summers, HMPD operations manager and commander of the SWAT team, “being able to switch from AC to DC [direct current] as needed allows us to keep using the ICRI should we decide to cut the building’s power to get an advantage over the hostage-takers.”

The ICRI was developed by Communications-Applied Technology, Reston, Virginia. Seth Leyman, president and founder of the company, developed the ICRI with the support of the U.S. Department of Justice Office of Law Enforcement Technology Commercialization (OLETC). The OLETC not only helped fund the research for the interface but also gave Leyman a ringside seat at the agency’s annual “mock prison riot,” which is staged inside an empty West Virginia penitentiary. The event is used to train hundreds of police and correctional officers who must deal with unruly inmates—played by students and other officers—in a realistic setting.

In addition to linking police radios, the ICRI is providing the U.S. armed services with interoperability between “green gear” radios with different waveforms and/or operating bands, Leyman says. “With an ICRI, a frequency hopping SINCGARS [single channel ground and airborne radio system] user can seamlessly talk to MBITR [multiband inter/intra team radio], XTS-5000 and even old PRC-127 users at the same time,” he explains.

Functionally, the ICRI is a ruggedized “black box” with ports for connecting radios, a telephone or Nextel cellular telephone and power. The interface does not include any radios or telephones. Once connected, the ICRI sends audio between the connected devices.

The interface can be purchased with reels of extension cable so it can be connected to one or more radios in different locations away from the unit. As a result, a radio can be connected to an ICRI then mounted at the top of a building or bucket truck to improve signal coverage. Or the extension cables can be used to interconnect the ICRI with a more powerful mobile transceiver. The transceiver serves as a repeater that can be accessed by other radio/telephone networks connected to the ICRI.

For the Hagerstown police, having access to a repeater is vital because Hagerstown is only 12 miles away from Camp David. When the president comes to Camp David, HMPD personnel support the Washington County Sheriff’s Department to provide security. “Normally, they can patch through to us through HMPD dispatch, but sometimes their radios can’t hit our towers. When this happens, we use the ICRI to enable their radios to connect with ours,” Capt. Summers explains.

The extension cables also bring radio signals into electrically shielded areas. For instance, the 63rd WMD-CST helps civil authorities identify, contain and manage biological, chemical and radioactive threats discovered in the continental United States. To train for this task, personnel spend a lot of time suited-up inside confined spaces, where weapons may be produced or stored.

“We did one exercise in which we had to send a team member into a concrete cistern,” Sgt. Stapleton relates. “Normally, we would have had great difficulty in maintaining radio communications in such an environment. However, by attaching a radio to an ICRI cable and then lowering it into the cistern, the problem was solved. Whenever he needed to talk to us, the team member keyed his radio, which connected to the suspended handheld. The signal was carried up the extension cable to the ICRI, fed to a second radio above ground and rebroadcast on another frequency. For us to answer him, the process was simply reversed. The result was that we had no problem keeping in touch in a typically hostile radio situation,” he explains.

LeRoy Sisley, a fire fighter and communications specialist with the Seattle Fire Department, also has verified the ICRI’s extension capability. “I did extensive testing of the ICRI in very high frequency, ultrahigh frequency and 800 megahertz. I even used the extension cable to bring these signals into a basement,” Sisley says. “There’s no radio frequency around that can cut through 20 feet of reinforced concrete. However, by connecting an in-basement radio to the ICRI via an extension cable, bad reception was not an issue,” he notes. As a result of Sisley’s research, the Seattle Fire Department is now purchasing its own ICRI.

Capt. Summers has found that there is some background noise in communications ported through the ICRI and some delay in the ICRI accepting an incoming transmission from a just-keyed radio. The noise is not a problem, he notes. “As for the keying delay? I just tell my officers to hit the button and pause to think about what they’re going to say. This one- or two-second pause gives the ICRI time to give their transmission priority and prevents their first words from being lost,” he says.

A second limitation of the ICRI is its lack of onboard processing and presets. For instance, every time a two-talk group ICRI is deployed, the operator has to flip the A/B toggle switches manually to create the desired talk groups.

Because the ICRI does not include radios, departments must own up-to-date equipment to establish interoperability using the interface. “Not every officer takes good care of his equipment,” Capt. Summers notes. “It’s tough if you have to use such equipment to create interoperable radio links at the scene, but sometimes you do.”

James Careless is a freelance journalist who specializes in first responder communications.

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