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So, I have three USB A devices.

  1. Logitech wired keyboard
  2. Logitech wireless mouse with a USB A receiver
  3. Logitech webcam

In my previous job, I was given a Lenovo Windows laptop. I had a USB 3.0 switch that I bought from Amazon. I used it to switch my devices between my Desktop computer and office laptop.

Now I switched jobs and I was given a 2019 16" MacBook Pro. I purchased a USB A to C cable and I tried to hook the USB 3.0 Switch to my MacBook Pro, but the MacBook is not recognizing the devices attached to the switch.

What can I purchase? What can I do in this situation? My desk does not have enough space for another set of mouse, keyboard, & webcam.

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  • Just to confirm: are you still using windows PC? if not, your (almost only) option is to buy Mac compatible keyboard. Using Windows' keyboard can be frustrating, by lacking command key/option key, at least for me.
    – Skye-AT
    Dec 9, 2021 at 5:36
  • Have you installed the Logitech drivers?
    – Tetsujin
    Dec 9, 2021 at 7:09
  • With your KVM and devices attached and switched over to your Mac, please amend your question with the output of this command: system_profiler SPUSBDataType
    – pion
    Dec 9, 2021 at 8:30

2 Answers 2

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Let me guess, the USB switch looks something like this one:

enter image description here

I suspect the reason the USB switch is not working any more is because the switch was designed in a way that violated the USB specification, using USB-A ports for both input and output, and you bought a cable for it that adheres to the USB specification.

Using USB-A ports for input is not just violating the USB specifications but is a potential fire hazard. The USB-A to USB-A cables that your switch almost certainly came with will connect the power supply pins straight through, if these cables are mistaken for cables that do comply with the USB specification (which will comply by not connecting the power supply pins) and are used to connect two computers together the cable will short circuit the power supplies and potentially break or burn something. A USB-C to USB-A cable that complies with the USB specification, which is most likely the kind you bought, will not supply power to the USB switch. No power to the switch means no power to the devices, and no power to the devices means they will not work.

Again I am speculating here because you did not provide a description of your USB switch. I've seen these kinds of switches before, they appear to be popular. They are likely popular because they are cheap. They are cheap because they used a cheap design that does not meet the USB specifications.

What should you do about it? Throw away the switch and the cables, then be thankful they didn't cause damage to anything. Then buy a USB switch, or KVM switch, that meets the USB specifications. How do you know the product meets the USB specifications? Look for USB certification on the box or in the product description.

enter image description here

The USB connectors should have the trademarked icon.

enter image description here

It's not illegal to sell cheap junk but it is illegal to put trademarked icons on items for sale without permission. Cheap junk will not get the attention of lawyers but use of trademarks without permission will. These products that violate the USB spec remain on the market by not using any trademarks, and through clever wording of their claims. They claim, "Compatible with most USB devices." It doesn't work with your USB device? Well, they didn't claim it was compatible with every device. They didn't claim to meet any testing for compatibility. Or claim to meet any testing for safety. It's sold "as is", if it doesn't work for you then that's on you.

One more time, I'm speculating on the source of the problem since you didn't specify the model of USB switch you have, I'm making an educated guess. It appears you already suspect the USB switch is the source of the problem and I agree.

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  • Your hypothesis is right I think. The USB C to USB A cable I had did not supply power. Usually, when I use one of the cables that the switch came with, to connect my computer to the switch and my computer was powered on, it would let me switch to that computer's side. With the cable that I bought, it was not even switching over to that side.
    – Aditya
    Dec 15, 2021 at 15:34
  • I don't think this answer is fully correct. I have bough one of those switches and plugged them via a "normal" USB-A to USB-C cable into my desktop Windows computer, and it works. This cable didn't come with this switch, it came with my mainstrean mobile phone to be used as a charging cable and data cable. This doesn't work when I plug it into my macbook though. Also, how exactly is a "USB-Compliant" KVM or Switch gonna make the connection, should it be using a USB-B port instead? Feb 23 at 13:41
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You can only connect a USB hub via the Thunderbolt ports on the MacBook Pro. You CAN NOT connect a USB Switch via the Thunderbolt ports on the MacBook Pro.

MacGuffin is correct 100% that is the USB protocol designed for. Upstream port can not become downstream port at the same time in this case.

You should have a DisplayPort KVM switch instead. Put a docking station between your MBP and the KVM switch. And plug all the shared monitor(s), keyboard, mouse and other sharing devices to the console connections of the KVM switch.

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