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Apple's New Lightning Cable Dissected, Chips Analyzed

By Wesley Fenlon

A close look at Apple's Lightning cable figures out what what its various chips are for, but we still don't know how Lightning will affect third-party accessories in the future.

You know the age-old technology cycle: Big company releases new proprietary tech in an attempt to control usage and licensing, hackers tear it apart and release their own cheaper alternatives. With the iPhone 5's new 8-pin Lightning connector, Apple has tossed out the old 30-pin Dock Connector, and conveniently rendering all old iPhone accessories obsolete without a $30 adapter. Lightning is small, and better yet, reversible. And as a new teardown by Chipworks reveals, Lightning's tiny housing holds four chips that hint at how it works.

One of four chips Chipworks found inside the Lightning cable is TI's BQ02025, which likely houses some data-checking for the Lightning connection. Similar TI chips house CRC generators used to scrutinize the bits of transferred data for errors.

The Lightning cable is definitely "smarter" than its predecessor--because it has fewer pins, Apple had to design it to intelligently route data differently for different devices. Chipworks predicts that some of Apple's authentication patents will allow the cable to set up unique handshakes on a per-accessory basis so that, for example, a music dock could only access data related to music and not have access to your email or contacts. They also note that the chip could be used for more efficient battery charging.

A group called iPhone5Mod claims to have already cracked the secrets of the Lightning cable and is selling an alternative, but for 95 cents more than Apple's $19 cable. This is where the "security" of the Lightning cable gets a bit confusing. Chipworks calls the TI chip's CRC generator a security feature, but a detailed blog post by Rainer Brockerhoff points out that's not really the case. He writes:

Somewhat confusingly, Chipworks refer to CRC as a “security feature”, perhaps trying to tie into the authentication angle, but of course any serial protocol has some sort of CRC checking just to discard packets corrupted by noise.

Brockerhoff disputes claims made on several blogs that the Lightning cable houses any kind of authentication chip, writing "Recall how a similar flap about authentication chips in Apple’s headphone cables was finally put to rest? It’s the same thing; the chip in headphones simply implemented Apple’s signalling protocol to control iPods from the headphone cable controls. The chip in the Lightning connector simply implements Apple’s connector recognition protocol and switches charging/supply current."

If iPhone5Mod have indeed copied the Lightning cable already, a flood of cheaper cables may be coming soon. We're mostly interested in seeing how Apple's adaptive cable changes how the iPhone interacts with accessories, and whether Brockerhoff's theory that Lightning could possibly support USB 3.0 turns out to be true.