| 摘要 |
PROBLEM TO BE SOLVED: To provide an alarm capable of easily switching the directivity of an antenna without providing a plurality of antennas, and preventing the structure of a fire alarm from being made complicate, resulting in improvement in productivity and satisfactory wireless communication with fire alarms installed in various directions by one antenna.SOLUTION: An alarm 10 configured to, when detecting the abnormality of a monitoring area, performing notification of the abnormality of the monitoring area by a notification part 12, and to wirelessly transmitting an abnormality signal includes: a communication part 13; a plurality of ground patterns 15; a connection part 16 for connecting the communication part 13 to any of the plurality of ground patterns 15; and a connection control part 17 for allowing the connection part 16 to successively connect the communication part to each of the plurality of ground patterns 15.SELECTED DRAWING: Figure 1 |
