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Title explains it.

Imagine this example, Host computer connects to a Client computer via male/male usb connection. Client computer acknowledges this connection as a new device, in this case a keyboard. The host computer can now send key events to the client computer and the client computer would process them as a normal keyboard event.

I did a whole lot of searching in the internet and really have drove down many dead ends. Any tips would be appreciated.

Note* this is a physical connection. The client computer should not have to install any software for this to function (The host will completely spoof as a keyboard).

Cfinley
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Joe C
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3 Answers3

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USB has two modes: Master and slave.

Usually a device only supports a single mode. E.g. a mouse is a slave, a pendrive is a slave, a keyboard is a slave. A computer is usually a master.

Masters and slaves can communicate with each other.
Slave <--> slave and Master <--> Master does not work.

Master and slave use different plugs to prevent people from making the wrong connection.

Picture of a USB master and slave plug

Only changing the connector does not change this.


In order to use the PC as a keyboard it will need to be able to emulate a slave. Some USB chipsets can this. Most can not. Those who can usually are connected via an AB connector.

Master only uses A (left side of above picture), or mini-A,
Slave only uses B (right side of above picture), or mini B. Devices which can do both usually come with an AB connector.

Wikipedia has a nice list of these connectors and interfaces: Notice that some of these support both a and B connections.

enter image description here

Summarising: you will need to have a non standard USB controller/chipset and a special cable. So yes, it can be done. But not by just modifying a cable and running a special program on the computer which needs to emulate the keyboard.

Hennes
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There are USB devise like this can do the job: https://www.amazon.com/gp/product/B019DI3RV8/ref=ask_ql_qh_dp_hza

But it is not a simple male/male wire.

There are also tools: https://mtlynch.io/key-mime-pi/

It needs USB On-The-Go which Raspberry Pi support it. I'm not sure if normal PC support it.

linjunhalida
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While its not particularly easy to emulate a keyboard over the USB port, you might find it far easier to use an Arduino Pro Micro/Leonardo/Some other MCU to inject keystrokes like a keyboard. This is trivially easy if youve got an Arduino IDE and a compatible MCU like a Pro Micro to hand. I suppose you could then issue commands to it via Bluetooth (by use of, say, a HC05) and then it would inject the keys after receiving them. This is way more electronics based than the answer you would like but it's surefire to work - unlike reconfiguring anything on your computer to try and re-jig the USB into a slave device of some sort

QuickishFM
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