Computer manufacturer NCR, best known perhaps for making tills and cash machines, has filed a lawsuit against PDA firms Palm and Handspring. NCR alleges the companies have breached two of its patents.

NCR said the two biggest handheld makers had violated 1987 patents covering the idea of using docking stations. NCR wants compensation from Palm and Handspring for any loss of past or future sales. Palm and Handspring have denied the claims.

"We will be fighting this," said a spokesperson for Handspring. Handspring added that the claims held no merit, and both companies would be "standing together" to fight NCR. Palm said it could not comment on the case at this stage.

The suit has not shadowed today's launch of Palm's m500 and m505 handheld devices. The new devices work with expansion cards and an updated operating system.

Palm finally shook off a court case brought by Xerox last year after a three-year battle. Xerox said Palm's Graffiti handwriting recognition software copied a system developed by Xerox's research centre Parc, but last year the case was finally thrown out.