New rule rattles cell phone industry: "Come Nov. 24, the U.S. cell phone industry will lose the one thing that insulated it from true competition. In what could be the biggest event in the industry's 20-year history, a new rule will let consumers keep their cell phone numbers if they switch carriers. ...

"For 154 million U.S. cell phone customers, that will end the pain of changing phone numbers on business cards, in ads or in address books of family, friends and co-workers. ... About 24 million customers are expected to switch by June 2005, estimates the Management Network, a consulting firm. If so, 16% of the cell phone market could change hands — sinking some carriers while lifting others. ...

"'From an operational view ... this is the biggest thing that has hit the industry maybe ever,' says John Comisky, vice president of operations for Verizon Wireless. ...

"Not every cell phone user will be affected Nov. 24. And a smooth transition isn't certain. Issues: Availability. Number portability will only be available on Nov. 24 in more than 100 top metro areas. The FCC requires carriers to extend it nationwide by May. ...

"Timing. Carriers aim to make number switches in 2½ hours. The FCC wants them to hit that mark, but there are no established penalties if they don't. Depending on the carrier, "It can take anything from several hours to several days," says Jonathan Tinter, vice president of marketing strategies for AT&T Wireless, the No. 3 carrier. ...

"Landline transfers. The FCC also requires phone companies to switch some traditional home and business numbers—called landlines because they use wires—to cell phones. ... The cellular association, CTIA, estimates that because of the way wireless networks are set up, only 13% of wireless customers will be eligible for this. ..."