Just when you thought it was safe to curl up on the sofa and hide from the world, some of the largest technology companies are stepping up efforts to invade your living room with products designed to link televisions, computers and other home electronics. The makers of these high-end gadgets hope to redefine how homeowners watch television, surf the Web and listen to music.

Sony Corp.'s Airboard, a wireless screen first introduced to the Japanese market in December 2000, was the first attempt at such a radical redefinition of home entertainment.

Microsoft Corp. and others have since followed, making expensive bets that consumers will want to roll their computers and home electronics into one, and access the devices and the Internet from anywhere in the home. As Richard Chu, a Tokyo-based analyst at ING Barings Securities, puts it: "Everyone wants to be untethered."

The concept of the networked home is not new, but more sophisticated wireless technology, the proliferation of high-speed Internet services and streamlined hardware make the latest set of offerings more user-friendly and, in some cases, cheaper.

Sony recently showed off the Airboard2, a home-entertainment controller and wireless television as small and light as a laptop. A separate base station props up the screen, recharges the battery and serves as a hub connecting, for example, a DVD player, a videocassette recorder, television and other electronics, including those not made by Sony. Airboard2 is designed to let users control these devices, as well as type e-mail and surf the Web.

The key to the upgraded Airboard is its ability to wirelessly link to broadband Internet connections. This allows one person in the home to watch one program on the Airboard while someone else watches another on the television.

Improvements to the Airboard2, which is available only in Japan, include a larger, brighter screen (12.5 inches, or 31.7 centimeters), longer battery life (up to two hours) and ports for downloading and printing digital photos. Extra base stations can be set up around the house.

The Airboard is the brainchild of Satoru Maeda, 50, the free- spirited head of Sony's Personal IT TV Division, who got the idea a decade ago when he was developing digital cordless phones that sat in rechargers. "I knew that the digital phone would need base stations and if those were there, you could send all types of information through it," Mr. Maeda said. "That's when I struck on the idea of developing a home network."

Mr. Maeda also saw that Web-enabled TVs forced users to sit near their televisions to surf the web. "Then it came to me," he said. "If I could pick up the TV and carry it while it was connected, I could change the culture of watching television you could take it to the toilet, bath or bedroom."

Moxi Digital Inc.'s Moxi Media Center takes a similar approach in that it puts the television at the center of the network. Created by Steve Perlman, the inventor of WebTV, Moxi is part television receiver, part video player and part digital jukebox, all linked to the Internet. Similar to TiVo Inc.'s set-top digital video recorder, Moxi has an 80-gigabyte hard drive that stores 60 hours of video and hundreds of CDs.

The device can be linked to four television sets to allow family members to watch different shows simultaneously. The television receiver connects to a satellite dish or cable line, allowing Web surfing and video on demand. "It's a digital entertainment hub that does away with having 10 remote controls," said Gina Miller, a spokeswoman for Cl Inc. The Moxi Media Center will be introduced by the end of the year. The company has signed a distribution deal with the satellite TV provider EchoStar and is negotiating with other vendors.

Microsoft takes a slightly different approach. While Moxi puts its stand-alone hard drive at the center of the home network, Bill Gates, the Microsoft chairman, sees the personal computer as the home network's core. Microsoft says it will roll out a suite of new products, including Freestyle, an entertainment media center for the PC built in conjunction with Hewlett-Packard Co., NEC Corp. and Samsung Electronics Co.

For those who want their computer on the run, there is "Mira," a code name for a wireless flat-panel screen connected to a computer running the Windows XP operating system. Borrowing from the Airboard concept, the portable screen is designed to allow users to work on their computers from anywhere at house, as well as control DVD players and other electronics. Microsoft has not specified release dates for any of these products.

The Sony and Moxi devices were developed using little market research, instead relying on their inventors' hunches.

Sony also broke with practice and let four "interface designers," who normally inspect prototypes developed by engineers, design the Airboard's screens. This approach resulted in a product that is easy to use, but the Airboard's touch keyboard is small, so typing more than rudimentary e-mails is difficult.

Inevitably, these products raise questions about how much gadgetry consumers will use. Having Internet access and control of your home entertainment network is great, but analysts say that most consumers buy products for one primary use and rarely use the additional functions.

"TV anywhere is a killer app, but why even have a computer on it?" asked Tim Clark, strategy director at ION Global, a Tokyo-based Internet consultancy. Mr. Clark said that while the portable, rechargeable TV was a great idea, the other functions would probably be rarely used. Sony will not release sales figures for the Airboard, but analysts say sales have been limited. The upgraded version will be released in Japan this month and retail for about $1,000. Sony is considering releasing Airboard2 in the United States later this year.

Moxi will be leased via cable and satellite television providers for about $50 a month. Microsoft is developing the software and the concept for Mira, and is hoping that equipment manufacturers such as Dell Computer Corp. or Compaq Computer Corp. will produce and sell the equipment.

Matsushita Electric Industrial Co., Sanyo Electric Co., Samsung and other electronics makers also are designing home network systems, but many of these take a more utilitarian approach, linking microwave ovens, washing machines and such hardly exciting stuff.

Some analysts say the approach taken by Sony, Moxi and Microsoft could be more successful because most gadget lovers probably would rather spend their money on entertainment than on cutting-edge housekeeping.