Thunderbolt Cable Teardown Reveals Electronics and Firmware

As noted by Arstechnica and iFixIt, Apple's new $50 Thunderbolt cable is actually a "smart" or "active" cable that contains circuitry and firmware. Arstechnica explains:

A source within the telecom industry explained to Ars that active cables are commonly used at data rates above 5Gbps. These cables contain tiny chips at either end that are calibrated to the attenuation and dispersion properties of the wire between them. Compensating for these properties "greatly improves the signal-to-noise ratio" for high-bandwidth data transmission.

iFixIt tore down the new ThunderBolt cable and found two Gennum GN2033 chips in the connector, one on each side. Additional support chips and resistors were also found for total of 12 chips and "tons" of smaller electronic components.

QBZvGuXR2nRD64NM
Gennum's chip is described as a transceiver that enables "reliable data transfer at cutting-edge speeds over low cost, thin-gauge copper cables." Early benchmarks of Thunderbolt drive enclosures show massive improvements over FireWire 800.

One interesting benefit of this "active" cabling is that current Thunderbolt ports found in the iMac and MacBook Pro will be future-compatible with planned optical Thunderbolt cables. Optical cables were part of the original plans for Thunderbolt which promises to offer much higher speeds, but the first version released are based on traditional copper wiring. Intel still plans on upgrading to optical cabling in the future, and existing Thunderbolt devices should be compatible with new cabling. This was mentioned during the original Thunderbolt roll out.

...the port you'll find in new MacBook Pros and storage devices can actually take an optical cable when those are cost-effective enough to roll out, because Intel will eventually bake the optical transceivers into the cables themselves.

Ars, however, suggests that the high cost and complexity of the cabling may be a hurdle to widespread adoption of Thunderbolt.

Popular Stories

maxresdefault

Apple Shows Off a Key Reason to Upgrade to the iPhone 17

Saturday February 7, 2026 9:26 am PST by
Apple today shared an ad that shows how the upgraded Center Stage front camera on the latest iPhones improves the process of taking a group selfie. "Watch how the new front facing camera on iPhone 17 Pro takes group selfies that automatically expand and rotate as more people come into frame," says Apple. While the ad is focused on the iPhone 17 Pro and iPhone 17 Pro Max, the regular iPhone...
m5 macbook pro deal

Why You Shouldn't Buy the Next MacBook Pro

Tuesday February 10, 2026 4:27 pm PST by
Apple is planning to launch new MacBook Pro models as soon as early March, but if you can, this is one generation you should skip because there's something much better in the works. We're waiting on 14-inch and 16-inch MacBook Pro models with M5 Pro and M5 Max chips, with few changes other than the processor upgrade. There won't be any tweaks to the design or the display, but later this...
iOS 26

Apple Releases iOS 26.3 and iPadOS 26.3

Wednesday February 11, 2026 10:07 am PST by
Apple today released iOS 26.3 and iPadOS 26.3, the latest updates to the iOS 26 and iPadOS 26 operating systems that came out in September. The new software comes almost two months after Apple released iOS 26.2 and iPadOS 26.2. The new software can be downloaded on eligible iPhones and iPads over-the-air by going to Settings > General > Software Update. According to Apple's release notes, ...
apple wallet drivers license feature iPhone 15 pro

Apple Says These 7 U.S. States Plan to Offer iPhone Driver's Licenses

Monday February 9, 2026 6:24 am PST by
In select U.S. states, residents can add their driver's license or state ID to the Apple Wallet app on the iPhone and Apple Watch, and then use it to display proof of identity or age at select airports and businesses, and in select apps. The feature is currently available in 13 U.S. states and Puerto Rico, and it is expected to launch in at least seven more in the future. To set up the...
Apple Logo Zoomed

Apple Expected to Launch These 10+ Products Over the Coming Months

Tuesday February 10, 2026 6:33 am PST by
It has been a slow start to 2026 for Apple product launches, with only a new AirTag and a special Apple Watch band released so far. We are still waiting for MacBook Pro models with M5 Pro and M5 Max chips, the iPhone 17e, a lower-cost MacBook with an iPhone chip, long-rumored updates to the Apple TV and HomePod mini, and much more. Apple is expected to release/update the following products...

Top Rated Comments

cmaier Avatar
191 months ago
Yeah, I don't think Monoprice is going to sell these things for $8 like everyone expected.
Score: 47 Votes (Like | Disagree)
RoelJuun Avatar
191 months ago
And still everybody keeps telling that Apple isn't interested in de Pro market and thinks only of the consumers ;)
Score: 18 Votes (Like | Disagree)
191 months ago
Not entirely surprising.

Keep in mind, Thunderbolt is two 10Gbps channels. Let's face it -- 20Gbps aggregate bandwidth is a LOT of bandwidth for an external cable which is getting up there in numbers to rival the amount of memory bandwidth most commodity computer chipsets have (I think two-channel X68 is 21.6Gbps), and those chipsets aren't exactly dirt cheap. This is bandwidth normally the realm of single mode fiber optics for cabling, and even then, the equipment on either side of that single mode cable isn't cheap.

This is not a dumb piece of shielded wire. This is a PCI-E breakout.

This is why the first thunderbolt peripherals are DAS RAID arrays and FCAL HBAs. This is stuff really intended for the professional market at the moment, not consumer devices, as there isn't a consumer device need for this crazy (yes, it's crazy!) amount of bandwidth. Not until production significantly catches up will things start to become cheap enough to make consumer devices.

This is why Apple is pushing Thunderbolt. Even in it's first incarnation it is an insane amount of overkill. It will not be quickly obsolesced.
Score: 17 Votes (Like | Disagree)
Justinf79 Avatar
191 months ago
And that's why they're $50. :)
Score: 14 Votes (Like | Disagree)
Eduardo1971 Avatar
191 months ago
Wow; is this the first time that iFix it has torn down a cable?

Too funny.:)
Score: 14 Votes (Like | Disagree)
elithrar Avatar
191 months ago
Why couldn't apple just put those chips in the computer themselves.
My gut feeling was so they have an excuse to charge an arm and a leg for the cables.

Because the chips help with handling attenuation on the cable, and it's part of the Thunderbolt spec. Without the chips, reaching 20Gbps over copper is incredibly hard.

PS: Read http://news.ycombinator.com/item?id=2711918 for a better understanding.
Score: 9 Votes (Like | Disagree)