Ventura County's Reverse 911 system is up and running, but it's still missing the cell phone numbers of county residents.

Officials unveiled the system Wednesday at a news conference attended by three county supervisors and the leaders of police and fire departments from all over the county. In a fire or other emergency, it will be used to place automated calls to tell people in the affected areas about evacuations and other urgent information.

"It's our job to protect the public, and this is a great enhancement to our ability to do that," County Supervisor Peter Foy said.

Foy and Sheriff Bob Brooks also asked people to call or e-mail the county to have their cell phone numbers added to the Reverse 911 database, especially if they rely on cell phones as their only phone lines. The system now includes 636,000 home and business phone numbers.

To submit a cell phone or Voice Over Internet

Protocol number, call 648-9283 or send an e-mail to reverse911@ventura.org or visit the www.ventura.org Web site and click on the "Disaster Information" link.

The new system covers the entire county except for the cities of Ventura, Thousand Oaks and Simi Valley, which have their own systems either in place or in progress.

With Reverse 911, county, city, police or fire officials can record a message and deliver it to phone lines in any area they choose. Messages will be sent in English and Spanish.

"We can draw around an area as small as a city block, or around the whole county if we need to," said Erin Edinger, a program administrator with the Ventura County Sheriff's Office of Emergency Services.

The Reverse 911 system has 46 dedicated phone lines, which can place as many as 5,520 calls per hour. In a larger emergency, the county will use off-site phone lines that can make 240,000 calls per hour.

The system was already used successfully last fall, when the Ranch fire approached Piru and Fillmore. The system was in place, but it hadn't been tested yet, and Sheriff Bob Brooks decided to use it to notify Piru residents of an evacuation order.

The Sheriff's Office of Emergency Services placed 756 calls in about half an hour and then 756 more with the same message in Spanish.

Brooks said Reverse 911 will be used for fire evacuations like that one, and for hazardous material spills, urgent crime alerts and other emergencies.

"We want people to know that if we call, then it's an emergency, and the information is important," he said.

It can also be used to summon off-duty firefighters and other emergency workers, instead of manually calling from a department phone list.

The Reverse 911 system was created and installed by Sigma Communications, a company based in Indianapolis, at a cost of about $166,000 to the county, Edinger said.

It will cost about $120,000 a year to run the system, according to a report last year from Brooks to the Board of Supervisors. The cities that participate will reimburse the county for part of the cost, with their payments depending on the number of phone lines in the city. Fillmore will pay about $500 a year, and Oxnard will pay close to $9,000.