The Jan. 8 shootings in Tucson may have drawn interest toward law enforcement in Arizona's second-largest city, but another incident that highlighted the need to improve public safety communications for agencies across the entire nation occurred much earlier: on 9/11.

"Certainly the events of 9/11/2001 in New York and Washington showed all the necessity of interoperable communications," says Carl Drescher, an administrator of Information Technology for the City of Tucson, which is participating in the ambitious Pima County Wireless Integrated Network (PCWIN). The multi-agency program—for which voters authorized $92 million in a special bond election in 2004—is tasked with, among other goals, improving public safety radio interoperability to enable agencies to "talk with each other" on a single frequency band.

Contiguous jurisdiction incidents and multijurisdictional pursuits—not uncommon events in cities of all sizes these days—are classic cases that beg for interoperability between agencies, says project administrator Capt. Paul Wilson of the Pima County Sheriff's Department.

"You have multiple agencies chasing the bad guy and not being able to communicate directly with one another while they're doing that," he says. "[An additional problem is] not having your medical responders knowing what's going on during all of that, so that they can pre-stage where they need to be, so they can provide the most efficient, effective, and quick service."

The City of Tucson alone operates on a hodgepodge of venues: VHF and UHF analog systems, and 800 MHz digital frequencies. Motorola police two-way radios mostly use VHF (150 MHz). Fire and emergency medical services use UHF (450 MHz). Mobile data accessed in police vehicles and fire apparatus operate jointly on the 800 MHz radio system. And other city public works departments crowd into all three bands for voice communications.

"The radio system in its current configuration has been in operation since 1982," Drescher notes. "However, some of the original core system has been in operation since the early 1970s."

The linchpin of PCWIN's mission is to provide digital radio service to more than 30 police and fire agencies in Pima County, which covers an area of almost 9,200 square miles. Several additional 800 MHz frequencies have been licensed for public safety use in the new radio system, including some set aside as multi-agency "group talk" channels. The project will adapt and construct multiple radio towers to allow interconnectivity, and purchase compatible radio equipment (handheld and fixed mount) for which each agency will pay a monthly user fee per radio.

The final element is construction of a centralized, regional communications center for the sheriff's department and other agencies, as well as technological upgrades to existing facilities for Tucson police, fire, and city communications so that each site serves as a "live" backup to the other, in case operations are suddenly compromised or shut down. The entire project is expected to become operational in 2014.