Signalling that it, too, plans to contest patent claims by Rambus Inc., South Korea's Hyundai Electronics Industries Co. Ltd. said Wednesday it has filed a suit against the developer of high-speed memory interface technology.

The suit was filed both by Hyundai Electronics and its North American subsidiary, Hyundai Electronics America, in the U.S. District Court in San Jose. It seeks that the court rule certain patents owned by Rambus are "invalid, unenforceable and not infringed by any Hyundai products," the companies said in a statement.

"It is Hyundai's position that the patents held by Rambus are not being infringed by Hyundai's current product offerings," said the company in a statement.

In its own statement, Rambus said Wednesday it had initiated negotiations with Hyundai to license the use of Rambus' intellectual property by Hyundai in SDRAMs (synchronous dynamic random access memory) and DDR (Double Data Rate) SDRAMS. Rambus said Hyundai "abruptly cut off" discussions. Rambus said it is preparing a response to Hyundai's allegations and expects to prevail in the litigation.

Hyundai's suit comes a day after Micron Technologies Inc., a major U.S. memory chip producer, filed a similar suit against Rambus in the U.S. District Court in Delaware. [See "Micron Technologies Files Lawsuit Against Rambus," August 29.]The dispute stems from attempts by Rambus to collect royalty payments for technology that it claims is used in conventional DRAM (dynamic random access memory) chips and on which it holds patents.

It has already faced down Hitachi Ltd. and Toshiba Corp. and won -- both companies agreed to license the technology and pay Rambus a sum for each chip they produce -- and says it is in talks with all other major DRAM chip makers on similar pacts. [See "Toshiba, Rambus Sign SDRAM Licensing Deal," June 16, "Hitachi, Rambus End All Patent Disputes," June 22 and "Rambus in Patent Talks with All SDRAM Makers," August 23.]Rambus' claims sent shock waves through the memory chip industry because the technologies used in the chips have been, until now, jointly pooled under JEDEC, the Joint Electron Device Engineering Council, and made available to all manufacturers royalty free to ensure common standards among manufacturers and between memory and its associated controller chips.

Hyundai Electronics, in Seoul, can be contacted at +82-2-3459-5000 or found online at http://www.hei.co.kr/