1. Control system comprising: at least one controlled device controlled by a controller having receiving means for wirelessly receiving command signals, and having a first storage location for storing a personal ID or address, a second storage location for storing a network ID, and a third location for storing the ID of a remote control device; at least one user-operable remote control device designed for transmitting command signals; wherein a command signal comprises at least a first data portion containing a target address code, a second data portion containing a network ID code, a third data portion containing a sender address code, and a fourth data portion containing a command code; wherein the controller is capable of operating in a normal mode in which the controller, in response to receiving a control signal, reads the target address code from the first data portion and compares it with its personal ID in the first storage location, reads the network ID code from the second data portion and compares it with the network ID in the second storage location, and reads the sender address code from the third data portion and compares it with the remote control ID in the third storage location, and, if any one of these comparisons shows a mismatch, ignores the command code contained in the fourth data portion or otherwise executes the command code contained in the fourth data portion; wherein the controller is further capable of operating in a special NO NETWORK mode, in which the controller, in response to receiving a control signal having a reset command code contained in the fourth data portion, executes a response procedure irrespective of the contents of the first, second and third data portions.