The next time Charleston residents hear a siren in their neighborhood, they shouldn't be surprised if it's followed by a phone call.

The Charleston Police Department has unveiled its new reverse 911 system that notifies residents and businesses by phone when an emergency strikes their community or the entire city.

Police officials said they plan to use the system in the event of missing people, hazardous material spills, major police actions or impending storms. Within minutes, residents will know whether they should stay in their homes, evacuate or be on the lookout for a suspect or missing child.

"It's just another way to quickly notify the community of an emergency," Charleston Police Lt. Mike Thomas said.

Billy Wise, the department's telecommunications manager, said the technology mirrors that already in use by the Charleston County Sheriff's Office, which will make merging the dispatch centers seamless, he said.

The system can pinpoint certain areas or call the more than 100,000 residences and businesses at one time. Angela East, the department's communications supervisor, said residents can expect to receive a message within 10 minutes or so following an emergency.

City officials acknowledge that fewer households have landlines now that cell phones have become so popular. In the future, they said they plan to arrange for households to be able to add their cell phone numbers to the city database.