CLEVELAND -- Many people have cell phones in case there's an emergency, but if you are in trouble, your cell phone may not help you, according to Troubleshooter Chris Caswell.

Caswell offered some advice for when you can't get a signal.

Several cell phones were put to the test, and even in the areas where there are strong cell signals, some of the cell phones failed to reach a 911 operator.

With the cooperation of local emergency centers, Consumer Reports conducted tests in New York and Indiana.

The locations were chosen because they had one service provider with a strong signal and at least one with a weak signal.

Of the 18 phone and service combinations tested, nine failed to reach 911.

Consumer Reports said those phones had the technical capability of getting through to 911 because all of the phones, like most cell phones, were either dual mode or tri-mode.

"That means that not only will they connect digitally, but they also have analog mode," said David Pittle of Consumer Reports. "So if you're trying to reach an emergency number, 911, and you can't get through digitally, we think the phone should automatically switch to analog and use whatever service is available."

If you have trouble reaching 911, try these steps.

• If your phone says "No Service," dial anyway.
• If you are inside a car, get out and re-dial. Cars can block cell phone signals.
• Dial several times. It can take time for a tower to locate your phone.
• Try using another cell phone if one is available.

Companies that provide dual mode and tri-mode phones are Sprint PCS, Veriozon Wireless, AT&T and Cingular.