Time calibration method for security system using sensors

• US 20030105602A1
• Filed: 11/07/2002
• Published: 06/05/2003
• Est. Priority Date: 11/09/2001
• Status: Active Grant

• Current Assignee: Nihondensikougaku Company Limited
• Original Assignee: Nihondensikougaku Company Limited
• Inventors: Orita, Takehiro, Orita, Kouji, Kuriuchi, Kimito
• Granted Patent: US 7,024,325 B2
• Time in Patent Office: Days
• US Class Current: 702/89
• CPC Class Codes: G08B 25/10 using wireless transmission systems G08B25/009 takes precedence

Abstract

Among multiple surveillance devices for mechanical security monitoring provided in a security system using sensors at least one of the multiple surveillance devices is equipped with a receiver for receiving standard time data and the standard time data received by the receiver is sent over a distribution line to required surveillance devices not equipped with receivers. This enables highly accurate time calibration among the multiple surveillance devices for mechanical security monitoring to be efficiently achieved using a power-line carrier (PLC) technology and, as such, allows sharing of accurate time data among the surveillance devices.

Claims

1. A time calibration method for a security system using sensors that enables time calibration of clocks of multiple surveillance devices used by the security system, the method comprising:

a step of receiving standard time data in at least one of the multiple surveillance devices of the mechanical security system; and

a step of sending the standard time data received over a distribution line to required surveillance devices.

2. A time calibration method as claimed in claim 1, wherein each of said surveillance devices has a power-line carrier transceiver and the standard time data is send through the power-line carrier transceiver to the requirede surveillance devices.

3. A time calibration method as claimed in claim 1 or 2, wherein in the surveillance device the time data and an output data from the corresponding vendor(s) are stored in a memory.

4. A time calibration method as claimed in claim 1 or 2, wherein a time calibration is performed by overwriting the time data of the clock with the standard time data.