Researchers from the National Centre for Scientific Research (CNRS) warned in a newsletter Friday that French buyers of Apple's new iBook notebook computer could be in for a nasty surprise if they use the machine's nifty AirPort wireless transmitter for accessing the Internet.

As it happens, the device uses the same 2.4GHz waveband reserved by the French military, meaning an iBook user surfing the Web near an army unit could end up scrambling defense force communications - and thus face a 29,000-euro ($30,000) fine and six months in jail.

A clearly irked Rear Admiral Jacques Bizard, head of the National Military Bureau for Frequency Use, told AFP: "Unlike other countries in Europe, this waveband is allocated for military use in France."

He added: "Apple probably didn't think about it, and the problem wasn't resolved in time. But we're not going to scrap all our communications equipment simply because iBook has suddenly shown up."

Bizard said that under French law, any individual who wants to use the 2.4GHz waveband first has to gain approval. Several hundred such requests are made each year, mainly filed by companies who want to set up wireless data-transmission system, he said.

"Generally, there's no reason to turn them down," said Bizard. "But these are local, fixed networks. The iBook, however, is light and portable."

Apple France's marketing director, Hugues Asseman, said the iBook transmits to a small receiver, called AirPort, which itself is hooked to the telephone network for accessing the Internet, sending e-mail, receiving faxes and so-on. The idea is to give users mobility, and not require them to sit next to a telephone socket.

The transmitting range between the iBook and Airport is only 50 meters (162.5 feet), and there should be no trouble getting permission from the authorities, Asseman said.

"We have zero worries about putting it (AirPort) on the market," he said. "There should be no problem unless you are in a room next door to a military headquarters."

Bizard - whose office theoretically could get submerged with requests if iBook takes off in France - said military experts would dissect the iBook to test its range. Military sources said that 50-meter transmissions can carry for kilometers if they are carried out in optimum conditions in the open air.

Apple itself gives differing figures for the range of the innovative iBook, which, like the iMac desktop comes in bright colors. In its English-language promotional literature, it gives a transmitting range of "up to 150 feet," which is 46.5 meters.

AirPort is an option to iBook and is to be launched on the French market in mid-October.