Question: Cabling RPI again #183

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opened 2026-02-20 13:21:50 -05:00 by deekerman · 5 comments

deekerman commented

2026-02-20 13:21:50 -05:00

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Originally created by @polachz on GitHub (Mar 3, 2021).

Originally assigned to: @mdevaev on GitHub.

Hallo.

I have found the project yesterday and I'm impressed by the idea. But some things are not completely clear for me. Especially with connecting RPI to the server as keyboard/mouse

I have found the issue #11 but it didn't give me all answers. Maybe I do not understand RPI USB system completely. Can you please answer to me several questions?

Why on older RPI (3 and bellow) I can't use an USB/A port as keyboard or mouse emulator directly? Why I need to use Arduino here instead just connect RPI USB port with server USB port?
Why I need to use Spliiter cable on RPI4 instead just use usb-C port as power supply and another USB/A port as Keyboard/mouse?
If the reason for 2 is that power will be provided on the USB cable(and then some servers wont boot), isn't easier solution to cut off 5V wire from the cable and then use the RPI USB/A port to connect the server instead of provide Y splitter? Will this solution works or I'm missing something here?

Thank you so much for your help

Originally created by @polachz on GitHub (Mar 3, 2021). Originally assigned to: @mdevaev on GitHub. Hallo. I have found the project yesterday and I'm impressed by the idea. But some things are not completely clear for me. Especially with connecting RPI to the server as keyboard/mouse I have found the issue #11 but it didn't give me all answers. Maybe I do not understand RPI USB system completely. Can you please answer to me several questions? 1. Why on older RPI (3 and bellow) I can't use an USB/A port as keyboard or mouse emulator directly? Why I need to use Arduino here instead just connect RPI USB port with server USB port? 2. Why I need to use Spliiter cable on RPI4 instead just use usb-C port as power supply and another USB/A port as Keyboard/mouse? 3. If the reason for 2 is that power will be provided on the USB cable(and then some servers wont boot), isn't easier solution to cut off 5V wire from the cable and then use the RPI USB/A port to connect the server instead of provide Y splitter? Will this solution works or I'm missing something here? Thank you so much for your help

deekerman

2026-02-20 13:21:50 -05:00

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deekerman commented

2026-02-20 13:21:53 -05:00

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@mdevaev commented on GitHub (Mar 3, 2021):

Hello. There is a hardware difference between a USB host and a USB device. The USB-A ports on the Raspberry can only work in host mode. They are not able to emulate the device. All the other problems stem from here.

@mdevaev commented on GitHub (Mar 3, 2021): Hello. There is a hardware difference between a USB host and a USB device. The USB-A ports on the Raspberry can only work in host mode. They are not able to emulate the device. All the other problems stem from here.

deekerman commented

2026-02-20 13:21:53 -05:00

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@polachz commented on GitHub (Mar 3, 2021):

Thank you for the explanation! By quick googling with the provided knowledge I have found that to get what I want is possible only on RPI model A (USB port directly connected to controller, not to hub). But the RPI 3A (https://www.raspberrypi.org/products/raspberry-pi-3-model-a-plus/) has no enough power to provide KVM, right?

@polachz commented on GitHub (Mar 3, 2021): Thank you for the explanation! By quick googling with the provided knowledge I have found that to get what I want is possible only on RPI model A (USB port directly connected to controller, not to hub). But the RPI 3A (https://www.raspberrypi.org/products/raspberry-pi-3-model-a-plus/) has no enough power to provide KVM, right?

deekerman commented

2026-02-20 13:21:53 -05:00

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@mdevaev commented on GitHub (Mar 3, 2021):

This one has enough power, but it's not too convenient to use (no ethernet) and I don't support this device out of the box.

@mdevaev commented on GitHub (Mar 3, 2021): This one has enough power, but it's not too convenient to use (no ethernet) and I don't support this device out of the box.

deekerman commented

2026-02-20 13:21:54 -05:00

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@polachz commented on GitHub (Mar 3, 2021):

Ok. Thank you so much! It's enough from me. You can close the issue now.

@polachz commented on GitHub (Mar 3, 2021): Ok. Thank you so much! It's enough from me. You can close the issue now.

deekerman commented

2026-02-20 13:21:54 -05:00

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@mdevaev commented on GitHub (Mar 3, 2021):