| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To establish a system, by arranging a transmission antenna only on the indoor side for discriminating that a portable key exists inside or outside a closed space, in the system for opening a key arranged in a door by the portable key. <P>SOLUTION: This locking device is constituted for transmitting a transmission signal of two levels of at least a weak level and a strong level from a controller 10 connected to the transmission antenna arranged in the closed space. The key 15 of the door 7 is opened only when there is no response signal from the portable key 16 when transmitted at the weak level, and when responding from the portable key 16 at the strong level. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
