Computer to act as keyboard

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.

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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.