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I use an expensive wired USB ergonomic keyboard at work. The keyboard connects to my laptop via a USB hub. Everyday, I have to plug the keyboard in the morning and unplug in the evening. It’s USB connector is now becoming loose.

So I was hoping to add a USB extension cable and change the arrangement from

  1. Keyboard -> USB hub -> Laptop
  2. Keyboard -> USB Extension Cable -> USB Hub -> Laptop

I tried with multiple USB extension cable but the keyboard is not recognized. However this works:

  1. Keyboard -> USB Extension Cable -> Laptop

I cannot remove USB hub because the laptop USB socket is already loose.

Is there a reason why the USB extension cable will not work with the USB hub?

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  • Also, is it a powered or unpowered USB hub?
    – Journeyman Geek ♦
    Mar 14, 2015 at 8:19
  • Make is microsoft ergonomic keyboard 4000. The USB hub and USB extension cable are store brand that I bought (white labeled products USB 3.0 products amde in china). Belkin actually didn't work for me. Microsoft did not specify USB port. It is not a powered USB hub.
    – doon
    Mar 15, 2015 at 17:28
  • Microsoft documentation microsoft.com/hardware/en-in/p/…
    – doon
    Mar 15, 2015 at 17:29

2 Answers 2

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Shamelessly plagiarizing USB Cable Length Limitations And How To Break Them from yourcablestore.com (they're trying to sell you stuff anyway; like the shorter cable you need or a good powered hub):

USB 2.0

The 2.0 specification limits the length of a cable between USB 2.0 devices (Full Speed or Hi-Speed) to 5 meters (or about 16 feet and 5 inches). In other words, you cannot just connect a bunch of extension cables together (like taking a 6 foot cord and extending it with 4 other 6 foot extension cords) and run them 30 feet to another room. However, you can connect a 6 foot cable with a 10 foot extension cable for a total of 16 feet, which is below the maximum cable length for USB 2.0.

USB 3.0

The 3.0/3.1 specification does not specify a maximum cable length between USB 3.0/3.1 devices (SuperSpeed or SuperSpeed+), but there is a recommended length of 3 meters (or about 9 feet and 10 inches). However, the biggest limitation to the length of the cable is the quality of the cable. Results may vary, but with a high quality cable you should be able to go beyond 3 meters. However, to ensure you achieve the best results possible, use an active cable when going more than 10 feet (3 meters).

In order to go beyond these cable length limits (or recommended lengths) you need to use self-powered USB hubs or active (repeater) cables; both of which have their own limits as well. Other options such as USB over Ethernet or building your own USB bridge can extend the USB range further.

The USB 2.0 specification requires that cable delay be less than 5.2 ns per meter (192 000 km/s, which is close to the maximum achievable transmission speed for standard copper wire). -USB, WIKI

Remember these are the theoretical maximum lengths; your mileage will vary from cable to cable.

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  • Thanks. With hub and extension cable the total feet is around 6 which is less than USB 2 or 3. I will chech more on the info you provided and post any resutls if I get. Thanks for response
    – doon
    Mar 15, 2015 at 17:26
  • The length limits specified by USB assume a continuous cable, putting extension cables, hubs, or whatever in this will add noise, impedance mismatches, and more that will corrupt the signal somewhat at each connector. These discontinuities in the signal path will make it unlikely for the signal to survive the maximum allowed length. Repeaters can reconstruct the signal to make up for some noise and attenuation but they can't make up for the delay on the wire. There's tricks to get around the delay issue but at some point everyone runs out of tricks to pull from their hat.
    – MacGuffin
    Jan 10, 2022 at 1:53
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I do not know why your keyboard isn't rcognised, it sometimes happen so if the extension is long and of low quality.

I curently use a usb extension cable of 5m long and another of 1m long, if there is no problem with the extension(use it to connect any other devices like pendrive or use it on another pc) and it is of good quality, then there's something wrong with the keyboard.

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  • Thanks for hte prompt response. I modified the question to reflect that the keyboard is recognized with just the extension cable between the keyboard and laptop. So it isn ot really an extension cable issue but extension cable + USB hub issue. How do I figure out which extension cable is of a better quality
    – doon
    Mar 14, 2015 at 6:23

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