Mobile email patent holder NTP, the company that very nearly brought BlackBerry maker Research In Motion (RIM) to its knees, has turned its sights on a new target – Palm.

NTP’s lawsuit claims that certain Palm products infringe seven NTP patents. Palm said in a statement that it has been in occasional contact with NTP concerning a license to these patents. “When Palm last communicated with NTP many months ago, however, each of the patents already was the subject of re-examination proceedings by the US Patent and Trademark Office (PTO),” the PDA maker said.

Palm claims that all seven of the patents asserted are being re-examined by the PTO and have been rejected by the re-examiners as invalid. Some of the NTP patents also refer to a pager-based email service that has nothing in common with the devices invented by Palm, the company added.

Palm said it will “defend itself vigorously against the attempted misuse of the patent and judicial systems to extract monetary value for rights to patents that may ultimately have no value at all”.

In March of this year, Canadian vendor RIM coughed up $612.5m to put an end to four years of court battles and avert a shutdown of the BlackBerry service by settling with NTP.