A regional project to link emergency workers from Knoxville to as far south as Floyd County, Ga., is halfway complete.

A 12-county network that stretches across Southeast Tennessee and reaches into Knox County will allow emergency workers to travel throughout the region but use the same radio network, making communication easier, said Troy Spence, chairman of the Tennessee Valley Regional Communications Committee.

The 800-megahertz radio network "has grown to a massive thing," said Mr. Spence, who was in Chattanooga on Tuesday for the committee's monthly meeting.

The network now includes emergency services in all participating counties, Middle Tennessee State University and the Morgan County Correctional Complex, he said.

Six Southeast Tennessee counties and three North Georgia counties are testing coverage and finishing installation, Mr. Spence said, and 80 percent of the system's towers are installed.

Rhea, Meigs, Bradley, Hamilton, McMinn and Roane counties in Tennessee are testing it, as are Walker, Dade and Catoosa counties in Georgia, said Arnold Hooper, manager of electronic communications for Chattanooga.

"It brings us from multiple disparate systems onto one common platform," Mr. Hooper said. The project is scheduled to be finished by June 2010.

Knox, Anderson and Loudon counties in Tennessee have not begun testing, he said.

Eighty percent of the $22.5 million project was funded by the federal government. Tennessee picked up $2.7 million in state costs, while Dade, Catoosa and Walker counties paid $1.4 million through local taxes, said Mr. Hooper and Catoosa County Sheriff's Office Maj. Gary Sisk, who works with the project in the Georgia counties.

Chattanooga had an 800-megahertz system in 1995 and added Hamilton County in 1999. Catoosa County joined the system in 2006, which helped show regional cooperation when leaders sought funding for the federal project, Mr. Hooper said.

Catoosa Sheriff Phil Summers said tests in his county show that mobile radios have 99 percent coverage compared to 70 percent on the old system and portable radios have 95 percent coverage compared to 50 percent on the old system.

He said when counties pay the cost to upgrade their systems and join the network, they get 12 networks for the price of one.