The complete cell-phone guide: 1 - service shortcomings.(Special Section)(Cover Story)(Industry Overview)

Even if you have a cell phone, you may be thinking about a new one--or a new carrier. Each year one in four users "churn," or jump to a new carrier, looking for lower rates, better service, fewer billing problems--or all of those quealities.

This special 13-page section can help you find better service, better rates, and a better phone.

(1) Service shortcomings

Why you can't always count on a cell phone when you need it. How to get better service.

Sept. 11 became a proving ground for emergency calling, especially from the cell phones on which 123 million Americans depend. On normal days cellular carries roughly 30 percent of 911 calls. Total cellular traffic nearly doubled in the hours following the terrorist attacks. That's when the thousands of people trying to make a call learned not only how vital cell phones have become, but how fickle cellular networks can be.

"We had the highest calling volume we've ever had," said Danielle Perry, a spokeswoman for AT&T Wireless. Many people in New York City and Washington, D.C., heard only the fast busy signal that means the network can't handle another call. Rescue workers using cell phones were as stymied as anyone.

CELLULAR BUSINESS, AS USUAL

The past two years have seen cellular subscribers soar by more than 40 percent, to 123 million. And Americans' cell-phone use has risen sharply, from 89 billion minutes in 1998 to nearly 200 billion in just the first six months of last year.

Americans are clearly willing to forgive a lot for those minutes. Telephia, a San Francisco company that measures network performance, pegs the chances of getting disconnected at 2 percent in a 2-minute cell-phone call. William E. Kennard, …