Remote control devices have long been known in the radio and television fields and they make it possible, preferably without the use of wires, to carry out switching operations on equipment. The best known of such remote control devices are those used for the remote control of television receivers, in which the instruction signals are transmitted ultrasonically or by infrared light. Television receivers can be switched on and off by means of such remote control devices. It is also possible to select different television programs or to change the volume, color saturation and other functions. However, these known remote control devices are generally only intended for the remote control of a single item of equipment, e.g. a television receiver or a video recorder. Since nowadays many households have several items of electronic equipment, disadvantages result from the association of a separate remote control device with each individual radio, television receiver or video recorder, because this requires the existence and operation of several remote control devices.
Remote control devices have already been proposed which make it possible to control remotely several items of equipment. A special problem in the design of such remote control devices is that a plurality of functions has to be fulfilled. If a particular button is associated with each of these functions, a very unwieldy remote control device is obtained which is difficult to supervise. A modern home can have as many as ten remotely controlled items of equipment, i.e. a television receiver, a record player, a tape recorder, an audio cassette player, a video recorder, a picture record player, a compact disc player, a tuner, an amplifier and a video camera. If it is also borne in mind that modern colour televisions fulfil numerous additional functions, e.g. display text, video text, stereo or two-channel sound, there are so many functions that a hundred operating buttons or even more would be necessary. A remote control device with so many buttons would be unwieldy and difficult to operate.
Remote control devices for several items of equipment have also been proposed in which all or several buttons carry out several functions. Generally a change-over switch is provided, so that it is possible to switch between individual items of equipment which have to be remotely controlled. In the "television receiver" position, the individual buttons of the remote control device will then have different functions to those e.g. in the "tuner" position. Whereas it is relatively easy to bring about switching from "television" to "tuner" etc. by using a slide switch or the like, it is much more difficult to show to the remote control device user which particular function is instantaneously associated with a particular key. Attempts have been made to solve this problem in that the different functions are written under the individual keys. This made it possible to keep the particular functions for each equipment to be remotely controlled in a specific color. Thus, e.g. in the "television" position, the red words under a key applied, whereas in the "record player" position the green terms applied. However, it is difficult to follow this solution, because several terms have to be written under one another, which either leads to barely legible inscriptions or to a need for a very large amount of space for these inscriptions.