NEW YORK (AP) _ Despite an end-of-2005 goal to equip all emergency dispatch centers with the ability to locate a cell phone user who dials 911, a congressional report finds that some states will need another five years or more, while others may never reach full availability.

The Government Accountability Office, the investigative arm of Congress, noted that the deployment of ``enhanced 911'' location capabilities had tripled during 2004 and 2005 among the nation's more than 6,000 dispatch centers.

Still, by late 2005, just 57 percent of the centers had upgraded their systems so their dispatchers could receive information from cell phone companies to pinpoint a 911 caller's location within a few hundred yards, the GAO said, citing data from the National Emergency Number Association. That compared with 18 percent in late 2003.

The deployment of so-called E911 is a two-piece puzzle, as both cell phone companies and the emergency dispatch facilities need to upgrade their systems.

The federal government has no control over the state- and local-run dispatch centers. So only the wireless companies are actually covered by the 2005 goal for full deployment first set by the federal government ten years ago. Some cellular carriers have asked for extensions.

The GAO report was based on a survey of local officials that drew responses from every state except Alaska, Colorado, Nevada, New York, Oklahoma and South Dakota. Officials from Washington, D.C., also failed to respond.

Georgia, Ohio, Pennsylvania and West Virginia told the GAO it would take up to five years to have E911 fully implemented with at least one cell phone carrier. Kansas, Mississippi and Texas said the deployment would take even longer. Alabama, Arizona, Idaho, Illinois and Wisconsin said full implementation ``may never be complete.''