Mackinac Island should have Enhanced 9-1-1 service by late July, following verification of about 1,000 addresses and telephone numbers.

"We're really close," said Bryce Tracy, the Mackinac County 911 coordinator who is working with AT&T on the project.

Mackinac Island joined the Mackinac County Enhanced 9-1-1 emergency telephone service in 2002, but has not been able to take advantage of the enhanced features until it created an address system. With Enhanced 9-1-1, callers are identified by their addresses, so responders automatically know where to go and, in some cases, important medical histories of residents.

An addressing system for lots and buildings on Mackinac Island was adopted in April 2006, and property owners were required to post the numbers on their property by July 1 2007.

Since then, the city, the county 9-1-1 office, and AT&T have been checking addresses and telephone numbers to make sure they are correct. In the meantime, basic 9-1-1 service is being used on the Island. That puts a caller in touch with the dispatch center, but callers must tell the dispatchers where they are.

With enhanced 911, dispatchers will be able to locate any caller from any land line on Mackinac Island without needing directions, although dispatchers may still ask the caller for directions to verify, said Mr. Tracy.

Cellular telephone users can also be pinpointed as close as 50 feet away on the Island, although some cell phones work better than others at this time, said Mr. Tracy. He believes all telephone companies will come into compliance soon so any cell phone will be enhanced-911-friendly.

Roughly 500 residents live on the Island year-around. The Island's population balloons to between 10,000 and 30,000 people during the peak summer months.

"With more and more new residents coming in, and because their stay on the Island ranges from year-around to three to six months out of the year, it makes Enhanced 911 that much more important," said Dennis Bradley, the Island's fire chief.

The former practice of knowing everybody in the community and where they are no longer holds true, he said.

Besides the thousands of visitors the Island sees each summer, "You have doctors and their families coming and going, you have families moving out of their old house into a new one, and having their children move into the old house," said Mr. Bradley.

Once he, the city, and AT&T match and verify the numbered address system with the telephone numbers, Mr. Tracy said, Enhanced 9-1-1 service will be turned on for the entire island at the same time.

Most of the rest of Mackinac County has been using Enhanced 9-1-1 service since 1998.