| 摘要 |
<p>There is provided an optical data communication apparatus for a facility having a location, characterized by a receiver located in the location, a motion detector located in the location, a plurality of portable transmitters for communicating with the receiver over optical wireless data links, each transmitter having a unique identification code and being carried by an individual, and means for actuating an alarm when an individual is detected in the location by the motion detector without a portable transmitter having an identification code indicating that the individual is permitted access to the location. <IMAGE></p> |
