Alarm system

• US 20040066292A1
• Filed: 09/19/2002
• Published: 04/08/2004
• Est. Priority Date: 03/21/2001
• Status: Active Grant

• Current Assignee: Optex Company Limited (OPTEX GROUP Co., Ltd.)
• Original Assignee: Optex Company Limited (OPTEX GROUP Co., Ltd.)
• Inventors: Iwasawa, Masashi
• Granted Patent: US 7,030,754 B2
• Time in Patent Office: Days
• US Class Current: 340/539.1
• CPC Class Codes: G08B 25/007 Details of data content structure of message packets; data protocols
• CPC Class Codes: G08B 25/10 using wireless transmission systems G08B25/009 takes precedence

Abstract

A transmitter 1 comprises a signaling history information transmission unit 15. After the transmitter 1 generates a detection signal, the signaling history information transmission unit 15 sends corresponding signaling history information to a regular signal transmission unit 13. From this regular signal transmission unit 13, the signaling history information and the regular signal are transmitted to the receiver 2. The signaling history information contains a count value which is updated at every transmission of the information. Even if the transmitter 1 generates a detection signal during communication failure, the receiver 2 can identify the time when the transmitter 1 generated the detection signal, based on the received count value.

Claims

1. An alarm system having a transmission means which generates a detection signal on detection of an object in a monitoring area, and a receiving means which generates an alarm signal on receiving the detection signal from the transmission means,

characterized in that the transmission means comprises a means for transmitting signaling history information, wherein, after the transmission means generates a detection signal on detection of an object, the signaling history information transmission means produces, at a predetermined time interval, signaling history information which relates to when the detection signal is generated, and allows the signaling history information to be received by the receiving means.

2. An alarm system according to claim 1,

wherein the signaling history information relates to when the detection signal is generated or how many times the signaling history information is transmitted.

3. An alarm system according to claim 1 or 2,

wherein the transmission means comprises a means for transmitting a regular signal to the receiving means at a predetermined time interval,

the regular signal transmission means being arranged to receive the signaling history information from the signaling history information transmission means, and to send the signaling history information and the regular signal to the receiving means.

4. An alarm system according to claim 3,

wherein the regular signal transmission means is arranged to send the regular signal at a shorter interval, if the signaling history information transmission means starts transmission of the signaling history information.

5. An alarm system according to any of claims 1 to 4,

wherein the signaling history information transmission means is arranged to end transmission of the signaling history information, after it sends the signaling history information for a predetermined period of time or a predetermined number of times.

6. An alarm system according to any of claims 1 to 4,

wherein the signaling history information transmission means is arranged to supply the receiving means with signaling history information which relates to all detection signals previously generated by the transmission means.

7. An alarm system according to claim 5,

wherein the signaling history information transmission means is arranged to supply the receiving means with signaling history information which relates to all detection signals previously generated by the transmission means.

8. An alarm system according to any of claims 1 to 4,

wherein the signaling history information transmission means is arranged to supply the receiving means with signaling history information which relates to the oldest detection signal among the detection signals previously generated by the transmission means.

9. An alarm system according to claim 5,

wherein the signaling history information transmission means is arranged to supply the receiving means with signaling history information which relates to the oldest detection signal among the detection signals previously generated by the transmission means.