| 摘要 |
PROBLEM TO BE SOLVED: To provide a general purpose system on an existing network system, allowing easily monitoring/recognizing of on/off state of a switch through a connected control device such as a computer, as well as checking of the on/off state from a remote place, while being cost effective and easy to install. SOLUTION: The switch is provided between the control device such as a computer and a terminal device having a network address (switch terminal device) using an existing protocol. On a predetermined period basis, a signal is sent from the control device such as a computer to the switch terminal device by adding an originating address and a terminating address. Connection status of the line is determined based on whether a reply signal is returned or not, thus allowing recognition of the on/off state of the switch. COPYRIGHT: (C)2005,JPO&NCIPI
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