The Time Warner Center in Manhattan, for example, has seamless cellular coverage throughout the building because of special antennas and repeaters that cost its owners about $ 1,000 each. The system ensures clear calls everywhere, from boiler room to penthouse.

But you don’t have to be a master of the universe to get good cellphone reception. Carriers and electronics manufacturers are now offering ways to make clear calls anywhere in your house, using devices that route calls through your home Internet connection or pump up the weak signals.

"Because more and more people are not taking landline telephones anymore, adding a signal booster is becoming much more popular," said Richard Holtz, president of Infinisys in Daytona Beach, Fla. His firm plans the placement of cellular boosters in high-rise buildings, dorms and offices.

"People are expecting perfect coverage everywhere," Mr. Holtz said, pointing out that being indoors or outdoors can make a big difference in call quality.

Many things get in the way of wireless signals. Trees and intervening buildings can degrade the signal from the cell tower, while brick walls and wallboard supports can block them completely. Sometimes many obstacles will conspire to create a "dead zone" of dropped and missed calls.

One solution to these problems is a device called a femtocell, which is sold only by cellphone carriers. These Internet-connected boxes act as tiny cell towers in your home or allow you to make calls over your local Wi-Fi network.

T-Mobile’s offering, called HotSpot @Home, uses specially outfitted phones to send calls through your Internet connection over a $ 30 router. The service costs $ 10 a month on top of your regular bill and allows unlimited calls between phones in the United States and Wi-Fi hotspots anywhere in the world. Once you leave the hotspot, the cellular wireless network takes over.

T-Mobile now has three Hot Spot @Home compatible phones, which cost no more than regular phones, and will release 10 more this summer. The company says it has trained its sales force to work with potential customers who may not be aware that their homes or offices are in a dead zone.

Verizon Wireless, AT&T Wireless and Sprint are all looking at femtocell products as well. Sprint is running trials in Denver, Indianapolis and Nashville with its own hardware.

A Verizon spokesman, John Czwartacki, said the company was still evaluating the technology. These carriers are likely to use a different kind of device that mimics a cell tower, avoiding the need to use special phones and Wi-Fi.

Hassan Ahmed, founder of Sonus Networks, a company that makes femtocells, said he believed that almost all of the carriers would add the technology to their product lines.

"I get great cellphone coverage around my house, and I get great Internet inside my house with DSL," Mr. Ahmed said. "However, when I’m in my house I can’t get any bars. A femtocell device is a win-win: it gives the carrier a way to improve their infrastructure and it gives me full bars." (NYT)