The Court of Appeals for the District of Columbia cited "procedural irregularities" in staying an order approved in September by the Federal Communications Commission, which would tighten standards that wireless carriers must meet for the accuracy of their e911 function, the FCC said.
In granting the stay on Tuesday, a three-judge panel of the appeals court said the wireless carriers are likely to succeed in their legal challenge of the FCC order.
The stay had been sought by a group of rural wireless phone companies who, along with major carriers such as AT&T, Verizon Wireless and Sprint Nextel, had sought to stop the new standards from going into effect while they pursue an appeal. (Verizon Wireless is a joint venture between Verizon Communications and Vodafone.)
FCC spokesman Clyde Ensslin issued a statement saying the agency "will comply with the court's order and continue to work with public safety and the wireless industry to ensure that the public can get help in times of emergency."
The new standards are aimed at allowing public safety workers to find someone who has dialed 911 from a cellular telephone.
Under FCC standards, wireless carriers using E911 systems must be able to determine a caller's location to within certain distances.
Under the new standards, the compliance of wireless carriers would no longer be averaged statewide or regionwide, a provision that has enabled them to meet standards even if the accuracy of their system is poor in some parts of a state.
The new standards would instead require wireless carriers to meet location accuracy standards within the area of each local emergency call center.
The FCC's order required wireless companies to meet annual benchmarks over the next five years and comply fully with the new standards by September 11, 2012.
In tightening the standards last year, FCC commissioners raised fears that current standards could lead emergency responders to search in the wrong place for an injured caller on a highway or fail to locate which floor a caller is on in a high-rise building.