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

iOS 26 Feature

iOS 26.1 to iOS 26.4 Will Add These New Features to Your iPhone

Saturday October 18, 2025 11:00 am PDT by
iOS 26 was released last month, but the software train never stops, and iOS 26.1 beta testing is already underway. So far, iOS 26.1 makes both Apple Intelligence and Live Translation on compatible AirPods available in additional languages, and it includes some other minor changes across the Apple Music, Calendar, Photos, Clock, and Safari apps. More features and changes will follow in future ...
ios 26 1 liquid glass opaque

iOS 26.1 Beta 4 Lets Users Control Liquid Glass Transparency with New Toggle

Monday October 20, 2025 10:57 am PDT by
With the fourth betas of iOS 26.1, iPadOS 26.1, and macOS 26.1, Apple has introduced a new setting that's designed to allow users to customize the look of Liquid Glass. The toggle lets users select from a clear look for Liquid Glass, or a tinted look. Clear is the current Liquid Glass design, which is more transparent and shows the background underneath buttons, bars, and menus, while tinted ...
iphone air thickness

Apple Said to Cut iPhone Air Production Amid Underwhelming Sales

Friday October 17, 2025 8:29 am PDT by
Apple plans to cut production of the iPhone Air amid underwhelming sales performance, Japan's Mizuho Securities believes (via The Elec). The Japanese investment banking and securities firm claims that the iPhone 17 Pro and iPhone 17 Pro Max are seeing higher sales than their predecessors during the same period last year, while the standard iPhone 17 is a major success, performing...
iOS 26

iOS 26.0.2 Update for iPhones Coming Soon

Friday October 17, 2025 7:35 am PDT by
Apple's software engineers continue to internally test iOS 26.0.2, according to MacRumors logs, which have been a reliable indicator of upcoming iOS versions. iOS 26.0.2 will be a minor update that addresses bugs and/or security vulnerabilities, but we do not know any specific details yet. The update will likely be released by the end of next week. Last month, Apple released iOS 26.0.1,...
Apple iPad Pro hero M5

New iPad Pro Has Six Key Upgrades Beyond M5 Chip

Saturday October 18, 2025 10:57 am PDT by
While the new iPad Pro's headline feature is the M5 chip, the device has some other changes, including N1 and C1X chips, faster storage speeds, and more. With the M5 chip, the new iPad Pro has up to a 20% faster CPU and up to a 40% faster GPU compared to the previous model with the M4 chip, according to Geekbench 6 results. Keep in mind that 256GB and 512GB configurations have a 9-core CPU,...
iPhone Siri Glow

Some Apple Employees Have 'Concerns' About iOS 26.4's Revamped Siri

Sunday October 19, 2025 7:39 am PDT by
iOS 26.4 is expected to introduce a revamped version of Siri powered by Apple Intelligence, but not everyone is satisfied with how well it works. In his Power On newsletter today, Bloomberg's Mark Gurman said some of Apple's software engineers have "concerns" about the overhauled Siri's performance. However, he did not provide any specific details about the shortcomings. iOS 26.4 will...
HomePod mini and Apple TV

Apple's Next Rumored Products: New HomePod Mini, Apple TV, and More

Thursday October 16, 2025 9:13 am PDT by
Apple on Wednesday updated the 14-inch MacBook Pro, iPad Pro, and Vision Pro with its next-generation M5 chip, but previous rumors have indicated that the company still plans to announce at least a few additional products before the end of the year. The following Apple products have at one point been rumored to be updated in 2025, although it is unclear if the timeframe for any of them has...
maxresdefault

Here's How the iOS 26.1 Transparency Toggle Changes Liquid Glass

Monday October 20, 2025 1:55 pm PDT by
With the fourth beta of iOS 26.1, Apple added a toggle that makes Liquid Glass more opaque and reduces transparency. We tested the beta to see where the toggle works and what it looks like. Subscribe to the MacRumors YouTube channel for more videos. If you have the latest iOS 26.1 beta, you can go to Settings > Display and Brightness to get to the new option. Tap on Liquid Glass, then...
m4 macbook air blue

M5 MacBook Air Coming Spring 2026 With M5 Mac Studio and Mac Mini in Development

Thursday October 16, 2025 3:57 pm PDT by
Apple plans to launch MacBook Air models equipped with the new M5 chip in spring 2026, according to Bloomberg's Mark Gurman. Apple is also working on M5 Pro and M5 Max MacBook Pro models that will come early in the year. Neither the MacBook Pro models nor the MacBook Air models are expected to get design changes, with Apple focusing on simple chip upgrades. In the case of the MacBook Pro, a m...

Top Rated Comments

cmaier Avatar
187 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
187 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)
mrfoof82 Avatar
187 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
187 months ago
And that's why they're $50. :)
Score: 14 Votes (Like | Disagree)
Eduardo1971 Avatar
187 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
187 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)