| 摘要 |
<P>PROBLEM TO BE SOLVED: To speedily support a case where an optical signal is not normally transmitted between a transmitter and a receiver of an information transmission device of an elevator. <P>SOLUTION: When a signal level of the optical signal transmitted from the transmitter 6b is lower than a predetermined level, the receiver 5b stops the output of the optical signal by transmitter 5a disposed together. When the output of the optical signal by transmitter 5a stops, a receiver 6a determines it and stops the output of the optical signal by transmitter 6b disposed together. Thus, even when the radiation direction of the optical signal by the transmitter 5a and 5b varies and the signal leaks out of a shaft, risk to a passenger by the optical signal can be prevented. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
