First announced in 2000, the Airboard marries the functions of a TV and Internet tablet PC into a portable device that allows access to TV, audio-visual devices or the Internet from anywhere within a 30m range of its base station.
The connection between the base and the monitor is through IEEE 802.11b wireless local area network (LAN) with 40-bit wireline equivalent privacy (WEP) encryption enabled.
With a 12.1in TFT, SVGA (800 by 600 pixel) resolution screen, the device is noticeably larger than the previous model, which had a 10.4in screen. Sony has also added a keyboard connector to make typing out long e-mail messages easier than using the on-screen keyboard.
The latest model boasts more memory: 64Mbytes in the Airboard and 32Mbytes in the base station, compared with a 16Mbyte/8Mbyte split in the previous model.
Battery life in the latest Airboard has also been improved, as a result of complaints from customers, said a Sony spokesman. Through use of a larger battery, portable life has been extended to approximately that of a notebook computer - up to two hours for the TV and three hours for Internet use.
There is also a mini-charging station, which the Airboard can plug into when batteries run low. Looking something like a personal digital assistant cradle, the charger is small enough to be carried around the house.
It is in the base station that some of the biggest changes have come. Sony has supplemented the telephone jack with an Ethernet socket for connection to broadband modems and added a second direct video input, making it possible to connect a DVD player and digital satellite tuner to the unit and access them both from the Airboard.
The 802.11b link has an added bonus when the Airboard is being used around the house: The tuner is housed in the base station and connected to a fixed antenna, which means a clean signal can be received anywhere in the house, unlike with portable TVs where the reception often differs widely around the home.
To complete the upgrade, Sony has added a USB interface and print server function to the base station. By connecting a printer through the USB interface, it is possible to print out text or images from the Airboard, via the wireless link back to the base station.
The Airboard IDT-LF2 will go on sale in Japan on 25 January for around 130,000 yen (£715). Sony does not plan to put the device on sale in foreign markets at present.