Phone companies prepare backup plans for Gustav

The tropical storm bearing down on the Gulf Coast could be a test for the country's wireless carriers.

Those carriers faced criticism and a regulatory push after Hurricane Katrina took out networks.

Dallas-based AT&T is the main landline phone company in the region and the country's largest wireless carrier. It's also added capacity, among a raft of preparations and upgrades to its Gulf Coast infrastructure over several years.

It has replaced some cables that are vulnerable to flooding with waterproof ones. Optical fiber has replaced copper wiring, which can short out when wet.

In the past year, Verizon Wireless has spent $137 million to enhance its Gulf Coast network. That includes doubling its capacity at regional switching centers to handle a barrage of calls when disaster strikes.

Tropical Storm Gustav was near Jamaica today, and forecasters said it could hit the Louisiana coast at the beginning of next week as a major hurricane.

If so, wireless networks would have two main vulnerabilities. The cell towers may be unhurt by the buffeting winds of a hurricane. But to keep working each needs electrical power and a connection to the larger network, usually via landline.

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