New Orleans remains shut off from the outside world, with virtually no phone service and repair crews not yet allowed to enter the flooded, battered city.
The various telephone companies have been unable to estimate when service might resume, since they have not yet been able to physically inspect the damage to their equipment.
The landline network has been out in most of the New Orleans area since the storm hit and most cell towers failed during the first few hours. Emergency generators kept some facilities up but they soon ran out of fuel or became water-logged.
The situation has not been much better for police, fire and other emergency workers. Although most of their base stations remained operational, with virtually no electricity in the city, workers have not been able to recharge the batteries on their hand-held units, rendering them useless.
It's not only New Orleans that's affected. Long-distance service for much of the Gulf Coast and Florida Panhandle is routed through giant switches in New Orleans. Many of those switches shut down because of water damage, interrupting calls that would normally pass through them.
Cingular Wireless said its network is operating on a "limited basis" in the New Orleans area, although service has been almost fully restored in Baton Rouge and parts of Alabama. Cingular is rolling out its own mobile cell sites, as well as bringing in back-up generators and additional fuel, a spokesman said.
Sprint said it has 100 engineers on site in Baton Rouge, where it is concentrating its recovery efforts. The company is preparing to roll out mobile cell sites in an effort to boost cellular capacity in areas where the wireless infrastructure is knocked out.
Hurricane Katrina demonstrates how few communications options most consumers have in the wake of a major disaster.
After a major storm, earthquake or fire, the landline network is often knocked out of service by damage to wires and cables. Extreme flooding can destroy network switching equipment and knock out emergency generators.
The cell phone network is even more vulnerable, as each tower must have electricity to operate. Most towers have very little back-up capacity and generators or batteries often fail after just a few hours.
Even when towers remain active, citizens can't recharge their battery-powered phones without electricity.
There are some options, such as satellite phones. But they are expensive, usually over $1,000, and are also limited by the battery life of the phone.
As many New Orleans residents have learned, cellular text messaging can be a last-ditch means of communicating; it requires less power than talking and does not require a constant connection. Also, those able to find a working Internet connection have been able to communicate via email and bulletin boards.
Some users of Sprint Nextel push-to-talk phones were surprised to find they could get through to others on their push-to-talk list, even in areas where the network was down. That's because the push-to-talk phones connect directly to each other, bypassing the network, although they have a range of just a few miles and battery life is still a problem.