Washington ? Consumers should be allowed to keep their phone numbers when they switch cellular providers, a federal court ruled Friday in rejecting an appeal by wireless companies.

Consumer advocates say the inability to retain numbers is one of the biggest barriers preventing more cell phone users from switching in search of better service and prices. The Federal Communications Commission is requiring wireless carriers to provide “number portability” by Nov. 24.

In April, attorneys for Verizon Wireless and the Cellular Telecommunications and Internet Assn. told a panel of the U.S. Court of Appeals for the District of Columbia that the FCC overstepped its authority by imposing the requirement. They said it would raise costs while doing little to increase competition.

The court rejected the challenge, calling the FCC’s action “permissible and reasonable.” The court also said the firms waited too long to object.