NEW YORK (CNN/Money) - The blackout of 2003 proved one thing to many cell phone users: the death of the traditional landline may be greatly exaggerated.

Many wireless customers in the New York metropolitan area, parts of the Midwest and Canada were unable to use their cell phones during the blackout, which made a frustrating situation even more annoying.

But landlines, including pay phones, (When was the last time you saw lines for one of those?) pretty much worked like a charm. So what went wrong?

In most cases, the biggest problem was a huge surge in volume (everybody all trying to make calls at the same time) that flooded the wireless spectrum, leading to many busy signals.

"Spectrum is a scarce resource and wireless companies build out their networks based on average expected usage levels," said Greg Gorbatenko, an analyst with Loop Capital Markets, an independent research firm focusing on telecom and cable. "A spike in demand can blow up the network and most cannot handle an emergency."

To that end, a spokesman for Sprint said that its wireless division handled three times the average daily volume in New York City on Thursday and Verizon Wireless said that call volume was four times normal in all the areas affected by the blackout.

"Think of it as five thousand people trying to get through your front door at once. It's going to be slow," said Mark Siegel, a spokesman for AT&T Wireless, which was still experiencing some cell phone service problems Friday morning.

But many had hoped that after the terrorist attacks on Sept. 11, 2001, wireless carriers would be better prepared for the next time there was an event that led to a substantial surge in calls.

However, the wireless telecom sector has many problems. Most carriers are faced with large debt loads. And because of intense competition (there are six major carriers nationwide) they are resorting to price wars to attract new subscribers. All that means that it has been difficult for the carriers to upgrade their networks to handle more calls and will probably remain so for the foreseeable future.

"It will be years before wireless carriers are at a level where they can handle the type of volume that landlines can," said Allan Tumolillo, chief operating officer of Probe Group, a telecom research firm.

Still volume wasn't the only problem. For example, while walking home Thursday, I completely lost my cell phone signal once I got into downtown Manhattan and headed over the Manhattan Bridge into Brooklyn. The service was not restored until my power went back on Friday morning and even then it was spotty at best. Meanwhile, my landline at home worked fine the whole time.

Why was that the case? Dan Wilinsky, a spokesman for Sprint said that while wireless carriers have ample power backup to protect their switches, that is not the case for all of the cell sites, which house the antennas that transmit the calls across a network. So as power slowly comes back to blacked-out areas, so should cell phone service.

Cingular said that as of Friday about 25 percent of its cell sites in Cleveland and New York City were still not operational and that more than 75 percent were out of commission in Detroit due to power outages.

Still, it's kind of alarming that cutting-edge technology such as wireless communications can be undermined by a glitch in a nineteenth-century innovation.

"Wireless is too dependent on the external power supply. And since wireless phones are becoming the main phone line for many people, the industry has to make sure that customers have the same kind of reliability as with landlines," said Jeff Kagan, an independent telecom analyst.

At the very least the blackout should put pressure on the major wireless carriers to bulk up coverage in already high-traffic networks and take more steps to insure that wireless antennas can keep running even in the event of a power outage.

And given the massive problems that cell phone users experienced on Thursday and Friday, this might convince some that having no landline at all is a bad idea.

"Wireless is not a failsafe. It's a telecommunications accessory," said Gorbatenko.