Dunwoody has decided to join the 911 center that serves Sandy Springs and Johns Creek.

After months of deliberation and several more weeks to review the city's projections, the Dunwoody City Council approved an agreement Monday night to go with the Chattahoochee River 911 Authority (ChatComm).

As part of the agreement, Dunwoody will sign a three-year, $3.2 million deal with ChatComm and give DeKalb County six months' notice that it will be leaving the county-run dispatch system.

"We've increased the ability of our first responders to respond," Councilman Robert Wittenstein said before the vote. ChatComm's "performance metrics are better in every way" than DeKalb's, he said.

The council approved the agreement by a vote of 5-2, with objections from Councilmen Denis Shortal and Danny Ross, who e-mailed a 14-page presentation to his colleagues outlining his concerns before the meeting.

In the presentation and later before the council, Ross argued that city officials should first come up with a master plan for public safety -- similar to what they have done for transportation and parks -- and that DeKalb's dispatch system wasn't nearly as bad as opponents had portrayed it.

“It is a life-or-death decision we are making tonight,” Ross said Monday. "This is not a good thing to do."

For months, Dunwoody had seemed poised to leave DeKalb's dispatch system and go with ChatComm -- launched by Sandy Springs and Johns Creek in 2009 after years of frustration with the Fulton County system. Those cities have strongly lobbied Dunwoody to join, hoping its addition would cut their costs for subsidizing the center by about a third.

Ross successfully persuaded the council to postpone a vote on the proposal earlier in the month. He expressed concern that revenue might run $200,000 less than expected, said the deal could cost more than $465,000 in additional expenses per year and raised the possibility of worse response time for fire and EMS services.

Proponents of ChatComm argued the cost differences -- while disagreeing with Ross' numbers -- would be worth it for a higher quality of service and the opportunity to work with neighboring communities.

"I believe ChatComm is worth every penny," Mayor Ken Wright said. "And partnering with Sandy Springs makes 100 percent sense."