Abstract: A controller that includes a number of switches is associated with a first appliance that has a number of operating states. In at least one of the operating states of the first appliance, the controller responds to certain switch actuations by causing it to perform a task; but when it is in another operating state, the same switch actuations have no meaning insofar as the first appliance is concerned, so the controller responds by transmitting data signals to a second appliance to have it perform a similar task. In this manner, a single controller can be used to control a number of appliances when a particular switch actuation has no meaning in the context of controlling the associated appliance. In an illustrative embodiment of the invention, the keypad of a telephone set is used to select a particular television station. Control signals are sent by the telephone to the television by spread spectrum data transmission over an AC power line. The data transmission format used is in accordance with the CEBUS.