Dan Frakes, with some great observations from his readers, writes about Lightning cables and the adapters Apple's new (30-pin and micro USB) being made available by Apple:
Astute readers may have noticed that the Lightning connector does not support analog audio-out, but the 30-pin adapters do. That's because hidden away inside each 30-pin adapter is a digital-to-analog converter (DAC) that converts the Lightning connector's digital audio signal to an analog version. (The inclusion of a DAC explains at least part of the price of the adapters.)
While I understand why people would be upset at having to buy adapters and potentially experiencing lost functionality, over time, this is only going to be a good thing. This is one of the changes I'm most looking forward to with the iPhone 5.
via DF