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

m1 chip slide

Five Years of Apple Silicon: M1 to M5 Performance Comparison

Monday November 10, 2025 1:08 pm PST by
Today marks the fifth anniversary of the Apple silicon chip that replaced Intel chips in Apple's Mac lineup. The first Apple silicon chip, the M1, was unveiled on November 10, 2020. The M1 debuted in the MacBook Air, Mac mini, and 13-inch MacBook Pro. The M1 chip was impressive when it launched, featuring the "world's fastest CPU core" and industry-leading performance per watt, and it's only ...
iOS 26

iOS 26.2 Available Next Month With These 8 New Features

Tuesday November 11, 2025 9:48 am PST by
Apple released the first iOS 26.2 beta last week. The upcoming update includes a handful of new features and changes on the iPhone, including a new Liquid Glass slider for the Lock Screen's clock, offline lyrics in Apple Music, and more. In a recent press release, Apple confirmed that iOS 26.2 will be released to all users in December, but it did not provide a specific release date....
All Screen iPhone 2027 Feature 1

Apple to Hide Selfie Camera Under Display of 20th Anniversary iPhone

Monday November 10, 2025 1:55 am PST by
Apple will conceal the front-facing camera under the screen of its 2027 iPhone, a Chinese leaker said today, corroborating reports that Apple's 20th anniversary iPhone will have no visible cutouts in the display. Weibo-based account Digital Chat Station said Apple's development of under-screen camera technology was progressing as planned for adoption in 2027, one year after it will...
iphone pocket%402x

Apple Debuts iPhone Pocket, a Limited Edition iPod Sock-Style Accessory

Tuesday November 11, 2025 1:23 am PST by
Apple has teamed up with Japanese fashion house ISSEY MIYAKE to launch iPhone Pocket, a 3D-knitted limited edition accessory designed to carry an iPhone, AirPods, and other everyday items. The accessory is like a stretchy pocket, not unlike an iPod Sock, but elongated to form a strap made of a ribbed, elastic textile that fully encloses an iPhone yet allows you to glimpse the display...
iphone air thinness

iPhone Air Sales Are So Bad That Apple's Delaying the Next-Generation Version

Monday November 10, 2025 11:41 am PST by
The thin, light iPhone Air sold so poorly that Apple has decided to delay the launch of the next-generation iPhone Air that was scheduled to come out alongside the iPhone 18 Pro, reports The Information. Apple initially planned to release a new iPhone Air in fall 2026, but now that's not going to happen. Since the iPhone Air launched in September, there have been reports of poor sales...
homepod mini colors

New HomePod Mini Coming Soon With These Features

Tuesday November 11, 2025 7:30 am PST by
Apple is expected to announce a new HomePod mini imminently, headlining with new chips. Here are all of the new features we're expecting. The second-generation HomePod mini is highly likely to contain a more up-to-date chip for more advanced computational audio and improved responsiveness. The current HomePod mini is equipped with the Apple Watch Series 5's S5 chip from 2019. Apple is likely ...
iphone black friday gold

The Best Early Black Friday iPhone Deals

Monday November 10, 2025 10:18 am PST by
Cellular carriers have always offered big savings on the newest iPhone models during the holidays, and Black Friday 2025 sales have kicked off at AT&T, Verizon, T-Mobile, and more. Right now we're tracking notable offers on the iPhone 17, iPhone 17 Pro, iPhone 17 Pro Max, and iPhone Air. For even more savings, keep an eye on older models during the holiday shopping season. Note: MacRumors is...
ios 26 digital id passport wallet

Apple Announces Launch of U.S. Passport Feature in iPhone's Wallet App

Wednesday November 12, 2025 9:15 am PST by
Apple today announced that iPhone users can now create a Digital ID in the Apple Wallet app based on information from their U.S. passport. To create and present a Digital ID based on a U.S. passport, you need: An iPhone 11 or later running iOS 26.1 or later, or an Apple Watch Series 6 or later running watchOS 26.1 or later Face ID or Touch ID and Bluetooth turned on An Apple Account ...
Early Black Friday Deals 1

The Best Early Black Friday Apple Deals on AirPods, Apple Watch, iPad, and More

Saturday November 8, 2025 6:16 am PST by
We're officially in the month of Black Friday, which will take place on Friday, November 28 in 2025. As always, this will be the best time of the year to shop for great deals, including popular Apple products like AirPods, iPad, Apple Watch, and more. In this article, the majority of the discounts will be found on Amazon. Note: MacRumors is an affiliate partner with some of these vendors. When ...
apple intelligence erroneous support list

Apple Intelligence Apparently Too Smart for M1 Macs After Listing Error

Wednesday November 12, 2025 2:49 am PST by
Apple's website is causing some confusion among Mac owners, and for good reason – its device compatibility listing for Apple Intelligence appears to have dropped support for M1 Macs. The U.S. version of its Apple Intelligence webpage has been updated at the bottom to list "M2 or later" Mac models as eligible for the AI features, replacing the long-standing "M1 and later" requirement....

Top Rated Comments

cmaier Avatar
188 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
188 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
188 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
188 months ago
And that's why they're $50. :)
Score: 14 Votes (Like | Disagree)
Eduardo1971 Avatar
188 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
188 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)