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Apple steps up iPod accessories 'tax'

But a change in strategy has left those at the bottom on top. The latest crop of iPods has eliminated the top connector, meaning that a vast number of add-ons will no longer work with the company's latest creations.

In some cases, whole classes of products won't work, such as the voice recorders and remote controls that plugged into the iPod's headphone jack and accompanying port. With other add-ons, such as the transmitters that send the iPod's tunes to a car stereo, the accessory market is divided into winners and losers.

Devices like the original Griffin iTrip won't work, because they require the top port, while others, such as Monster Cable's iCarPlay, are in the clear.

Griffin and others are responding quickly, though. Griffin announced a new version of its AirClick remote on Monday that connects to the bottom of the iPod, rather than the top.

Just knowing they won't be left out in the cold could be valuable to accessory makers, who typically have to build their products without any certain idea of what Apple plans to do next. Though Apple-related add-ons have long been a good market, accessory makers have also learned that they can be outflanked if Apple shifts course. Many companies first learned that lesson with the iMac, as Apple introduced models with new colours, rendering outmoded any accessories in the previous season's hues.

"We can ensure to the end user when they buy an iPod down the road that the compatibility is going to be there," said Randall Stowasser, a product manager for Belkin.

Avoiding obsolescence is also increasingly important to consumers, who, in some cases, are shelling out as much for iPod add-ons as for the pricey players themselves, which can cost as much as £299.

Both consumers and hardware makers have learned the hard way the cost of not having such guarantees. The most recent iPods -- the nano and the video-capable iPod -- lack a small connector near the headphone port. That change means that a whole crop of accessories, including some popular remote controls and RF transmitters, have become outdated.

But by removing that port, Apple has made the connection to its dock connector all the more valuable.

"It's the key to the kingdom," said Andrew Green, a vice president at Digital Lifestyle Outfitters, which specialises in iPod add-ons and is part of the Made for iPod programe. "Truly nothing can be done without it. It was one of two options yesterday -- it is truly the only option today."

Green said his company has focused all of its recent development on products that connect to the bottom of the iPod.

"Now we'll see rewards from doing so," he said.