The systems usually consist of a control pad that can vary in shape, size and
format depending on the user’s abilities and are generally operated using a single
switch. The options available appear as a list to the user e.g. light, fan, TV, radio,
telephone and a scanning method is employed to offer the range of options to the
user.
Infra-red (or radio frequency) operated power modules are plugged into standard
electrical sockets in the home and the device to be controlled by the user (e.g. a
fan or radio) is then plugged into these modules. The control pad stores the codes
to operate each of the devices to be operated in the same way that a standard
remote control can store all the codes required to operate a video recorder. Some
systems use radio frequency signals instead of infra red, in this way line of sight is
not required between the transmitter and the receiver.