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Here is a question a student asked me in one of my A+ certification classes: How can you tell a USB cable version? I honestly don't know the answer and I can't find one either.

USB cables are rated for versions 1, 1.1, 2, and now 3. I have seen their versions on the packaging, but never marked on the cable itself. Since the respective versions are manufactured differently, there is a difference between them.

So, how can you tell?

On Wikipedia: USB cables v.2 and earlier do use a "twisted pair" method, but it doesn't specify if the cables themselves are the same or different. Is the cable rating system for v.2 and earlier just marketing hype?

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    Don't forget that mini-usb cables also have different types, some for charging, some for data transfer, and some for headsets. Those kind are determined by having an extra pin (connection) that has a particular resistance to ground.
    – Keith
    Commented Aug 25, 2011 at 6:25
  • Additionally, the charging current that the cable can handle depends greatly on the thickness of the wires and not on USB version. Most cheap cables won't handle 1A charging as explained here.
    – rustyx
    Commented Aug 24, 2014 at 14:40
  • Benson Leung wrote what I consider to be the definitive article on this subject: people.kernel.org/bleung/… TLDR: You can't without some really specialized equipment, but maybe some modifications to the Linux kernel could expose this information in the future.
    – Ajedi32
    Commented Sep 29, 2023 at 14:18

7 Answers 7

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The USB-IF says all fully compliant USB 1.1 cables sold also meet the specifications for USB 2.0 Hi-Speed (although low quality, non-compliant cables may not work at the higher speed).

USB 3.0 cables include nine pins (instead of just four for USB 2.0) and have a larger "B" (device) end that will not fit into USB 2.0 printers, scanners, etc. These cables seem to often have a blue color and/or an "SS" (SuperSpeed) marking next to the USB logo.

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    Consider updating this answer to include info on USB-C connectors.
    – cp.engr
    Commented Jun 10, 2018 at 23:09
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This USB color table from Wikipedia shows how, in theory, you can use the color of the plastic inside the connector to tell different versions apart. (Realistically I've seen a lot of diversions from this, but frequently it is correct)

Color Location Description
Black or white Ports and plugs Type-A or type-B
Blue (Pantone 300C) Ports and plugs Type-A or type-B, SuperSpeed
Teal blue Ports and plugs Type-A or type-B, SuperSpeed+
Green Ports and plugs Type-A or type-B, Qualcomm Quick Charge (QC)
Purple Plugs only Type-A or USB-C, Huawei SuperCharge
Yellow or red Ports only High-current or sleep-and-charge
Orange Ports only High-retention connector, mostly used on industrial hardware
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  • I wa surprised that this is a standard thing, but the color seems to be definitive in certain situations, like a Black connector is always USB 2 and a blue is always 3. White is however ambiguous...
    – DrCord
    Commented May 16, 2016 at 23:43
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    @DrCord " I wa surprised that this is a standard thing " It's not a standard thing. I've seen plenty of products that violate this color scheme. Apple as an example is known for not color coding their ports and cables to this "standard". I had a charge only USB cable with a blue connector, not exactly superspeed if it doesn't move data. I say "had" because it was cheap and broke quite easily. I have a car charger with green USB-A and USB-C ports, which implies it supports Quick Charge, but I'm not seeing in the specs anything special about it. Buyer beware.
    – MacGuffin
    Commented Dec 2, 2021 at 4:44
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I don't think there's any difference between USB 1, 1.1 and 2 but version 3 has extra pins near the back as shown here. I'm not sure how obvious it would be just from looking at the cable since they're hidden at the back of the plug.

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Cables that adhere to the USB spec are required to indicate the USB version and data rate the cable was tested to meet. USB 1.1 and 2.0 cables will have the original USB "trident" icon. USB 3.x cables will have the trident with the additional stylized "SS" on the trident and often a small number 5, 10, or 20. The number indicates tested bandwidth in Gbps, and having no number means it was tested at 5 Gbps.

Newer USB4 cables will have a large 20 or 40 with the trident instead of the SS, but I have not seen this yet on any products. Examples of these icons, old and new, can be seen on the USB4 Wikipedia page: https://en.wikipedia.org/wiki/USB4#Data_transfer_modes

There are cables that will work for USB but lack the USB markings. These will be cheap imitations and since they don't adhere to the specified marking standard there's no telling what the cable is capable of doing without testing it. Testing these unmarked cables by plugging them into a computer can do damage so buyer beware.

There's other answers that will point out that there are cheap imitations that have the USB trademarked icons but these are quite rare. To get one of these would mean someone is really digging for a bargain or got very unlucky with an imitation making it to a reputable retailer. Making cheap cables is not illegal so there are plenty of those. Making cheap cables and putting trademarked icons on them without permission is illegal so they tend to disappear shortly after they appear.

Getting a bit off topic is the matter of Thunderbolt cables. Thunderbolt 3 and Thunderbolt 4 use the USB-C connector but will not always have the USB markings on the cables and ports. Thunderbolt 3 and 4 is a superset of the USB specification and so USB-C cables with the Thunderbolt markings will work with USB devices. Like with USB there's often a small number next to the icon, this does not indicate speed but version. I don't know if there's any real change made to the cable spec from 3 to 4 but those tested to the Thunderbolt 4 spec will have a small number 4. Some cables with USB-C connectors not marked with the Thunderbolt icon will work as a Thunderbolt cable. Some USB-C cables marked with Thunderbolt icons were tested to work with USB at all speeds, exceptions will be cables over one meter long that are optical cables or with signal amplifiers.

The color of the plastic in the connectors to indicate the kind of cable is either optional by the spec or was thought up by someone outside of the USB spec authors, it cannot be relied upon to indicate the cable capability.

So, look for the USB icons on the cable connectors to see if they've been tested to meet the USB spec. It's possible, but unlikely, someone put that icon on there without permission and it's a cheap imitation. No icons doesn't mean it's junk, though that's the safe bet, it means it was not tested for adhering to the spec. Most Thunderbolt cables will work as USB cables while few USB cables also work as Thunderbolt cables.

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This may help!

See this YouTube video for a detailed explanation on how you can identify real USB 3.0 cables vs fake ones, usually USB 2.0 ones.

In short USB 3.0 might have:

  • Blue connector: Some fake USB 3.0 cables may also have a blue bit but actually be USB 2.0.
  • SS Indicator: May have "SS" indication on cable (near connector) but most specifically.
  • More Connections: USB 3.0 has 9 (4+5) connectors, while USB 2.0 has just 4.

Also, if you connect a cable to a new computer/laptop and this complains your device could work faster, you know you have a fake USB 3.0 cable.

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Pictures for USB 2 vs. USB 3 (USB 3 has 5 extra pins), Type A connector:

Female:

enter image description here

Male: (below is USB 3 with its 5 extra pins).

enter image description here

(image source)

Wikipedia has nice schematics too, for different connector types:

enter image description here

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there is actually a difference. you will see a "+" for 2.0 on the end and " " nothing for a 1.0

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