Remember the story about the new iPods having DRM on the headphone interface, which would make it impossible to plug in third-party headphones unless they took a DRM license from Apple? Well, I was wrong.
No, the new iPods have a proprietary chip on the headphone interface that makes it illegal to manufacture third-party headphones unless you have a trademark license from Apple in order to claim "Made for iPod Certification". However, you can make your own iPod cans, provided you don't list them as "Made for iPod."
The BB Gadgets gang have all the details:
When reblogging iLounge's review, both the EFF and Boing Boing used the term "DRM" to describe the "auth" chip. BBG used the same term when questioning the function of the chip, which became understandably confusing for some, as an authentication chip, while perhaps using signaling that could not be legally reverse-engineered due to the restrictions in place from the Digital Millennium Copyright Act, does not affect the ability to listen to audio through generic, unlicensed headphones. (Except, of course, in the new Shuffle, which uses only in-line controls.)
For the record, we do not believe that the new iPod headphones with in-line remote use DRM that affects audio playback in any way.
That said, a three-button in-line remote could have been easily implemented by Apple without a microcontroller. While the in-line remote is simply an added convenience in most iPods, the iPod Shuffle has no controls on the device itself. To control the latest iPod, customers have no other choice but to use headphones made by manufacturers who have purchased a licensed authorization chip from Apple.