A California-based law firm has filed suit against Palm and former parent company 3Com, claiming that a feature used to synchronize data between Palm's handheld computers and a PC can damage PCs.

It is alleged that Palm and 3Com failed to warn users that the so-called HotSync feature in Palm handhelds could destroy the motherboard of certain models of PC. Palm declined to comment, saying it had not yet seen the lawsuit.

The suit was filed on behalf of two California Palm owners, and seeks class-action status for other users in the US who bought certain models of the Palm V and Palm Vx, and who may have been affected by the problem. The allegedly defective Palms have been on sale since 1999, and the law firm estimates that "hundreds of thousands" of users have been affected.

The lawsuit seeks unspecified monetary damages and an injunction requiring that Palm warns users that its PDAs (personal digital assistants) can harm their PCs.

Macworld has heard no reports of the problem affecting Macs. It's thought unlikely Macs are affected, because they do not connect directly to the Palm unit via a serial port, making use instead of a Mac converter.

One analyst said that if the allegations were true, it would be the first time he had heard of a serial port being damaged by a device attached to it. "If this is true, it sounds like there's some sort of hardware design problem in the cradle," speculated Chris Le Tocq, principal analyst with Guernsey Research.

"I wouldn't call it impossible, but at the very least extremely unusual," he added.