The invention concerns device control for enabling electrical or electronic devices to be controlled through computer systems. Employing the invention involves the use of one or more control interfaces which are capable of being used to interacting with a computer system or network, each interface typically comprising sheet material such as paper which has coded data disposed on it and which allows it to be used to interact with the computer system by use of a sensing device operated by a user. Through this interaction, data can be forwarded to the computer system from the control interface to effect in that system an operation relating to the functioning of the device.