| 摘要 |
The invention relates to an arrangement in code-protected electronic appliances, said arrangement being intended to encode for protection the appliance or appliances (6) located within the perimeters of a predetermined delimited area (3, 8), the arrangement employing a transmitter (4) adapted to emit at least one predetermined code signal and a receiver (7) mounted in said electronic appliance or appliances (6) to bring about that the appliance or appliances within said area become operable by receiving said at least one code signal emitted from the transmitter (4), said appliance or appliances being inoperable within as well as without said area when there is no coded signal from the transmitter. In addition the arrangement includes a filter (1) connected such that it will delimit that part of the power supply network (2) relating to said limited area (3, 8). Said transmitter (4) includes an encoding and decoding unit (5) and can be connected to the network (2) within said limited area. The filter (1) is connected to the power inlet to said area (3, 8) in such a way that an encoded signal emitted by the transmitter (4) can only be received by a receiver (7) located within the area. |
