Apple have confirmed that consumers with an iPod introduced in September 2007 might encounter some difficulties if they dock it with an speaker or docking system that was purchased in 2007 or earlier.

The culprit is an authentication chip embedded in the latest generation of iPods and required by Apple to be installed in new iPod speaker systems and in other new iPod accessories with video outputs. The chip isn't required for speaker systems or docks that lack video outputs.

The video outputs of current- and previous-generation iPod speaker systems and docks, including models sold during the Christmas 2007 selling season, may not work if consumers plug in one of the new iPods, suppliers said recently, according to TWICE Magazine in the USA.

New iPod speakers systems that companies plan to introduce next week at International CES, however, won't have that problem.

The chips were designed by Apple to thwart manufacturers that make unlicensed iPod speaker systems and accessories, thus helping licensed suppliers and retailers maintain their margins, suppliers explained. In what could be an unintended consequence, however, the chip in the new iPods could disable the video outputs of certain older-generation speaker systems and docks that were properly licensed by their suppliers at the time and are already in many consumers' hands.

Video outputs have been included in a high percentage of iPod speaker systems priced at more than $200 and on select iPod docks, suppliers said. The outputs are designed to display an iPod's video content, music metadata and menus on a connected TV screen.

When a new iPhone or iPod Touch is docked with a previous-generation speaker system or dock, the accessory's video outputs won't work at all, said Robert Heiblim, Altec Lansing senior marketing VP. If a new iPod Classic or Nano is docked with a previous-generation speaker system, only the S-Video output will work, Heiblim said. If the older speaker system or dock has only a composite-video output, the consumer is out of luck.