Loop transmission system
First Claim
1. A loop transmission system including a plurality of stations connected in series in a pair of looped transmission lines, wherein said plurality of stations include a supervising station and at least one terminal station,said supervising station comprising specific signal sending means for sending out a specific signal selected one of said pair of transmission lines which is to be operated as a spare line not used for data transmission, andsaid terminal station comprising specific signal detection means capable of detecting said specific signal from said specific signal sending means through either one of said pair of transmission lines, and discrimination means for controlling the transmission line through which said specific signal is detected by said detection means to operate as a spare transmission line which is not used for data transmission and for controlling the transmission line through which said specific signal is not detected to operate as a currently used transmission line for data transmission.
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Accused Products
Abstract
A loop transmission system including a plurality of stations connected in series in a looped transmission line to transfer data among the stations, wherein the stations include a supervising station and at least one terminal station and the transmission line is duplicated so that when a fault occurs in currently used one of the transmission lines, the other transmission line which has been used as a spare is used for transmission of data, while the supervising station sends out a specific signal to the spare transmission line and the terminal stations each determines one of the transmission lines through which the specific signal is detected, as the spare.
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Citations
14 Claims
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1. A loop transmission system including a plurality of stations connected in series in a pair of looped transmission lines, wherein said plurality of stations include a supervising station and at least one terminal station,
said supervising station comprising specific signal sending means for sending out a specific signal selected one of said pair of transmission lines which is to be operated as a spare line not used for data transmission, and said terminal station comprising specific signal detection means capable of detecting said specific signal from said specific signal sending means through either one of said pair of transmission lines, and discrimination means for controlling the transmission line through which said specific signal is detected by said detection means to operate as a spare transmission line which is not used for data transmission and for controlling the transmission line through which said specific signal is not detected to operate as a currently used transmission line for data transmission.
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4. A loop transmission system including a plurality of stations connected in series in a pair of looped transmission lines, wherein said plurality of stations include a supervising station and at least one terminal station,
said supervising station comprising specific signal sending means for sending out a specific signal to a selected one of said pair of transmission lines which is to be operated as a spare line not used for data transmission and specific data sending means for sending out a specific data message to a currently used one of said pair of transmission lines; - and
said terminal station comprising specific signal detection means capable of detecting said specific signal through either one of said pair of transmission lines, discriminating means for controlling the transmission line through which said specific signal is detected by said specific signal detection means to operate as a spare transmission line which is not used for data transmission and for controlling the transmission line through which said specific signal is not detected to operate as a currently used transmission line for data transmission, and status indication data sending means for sending out the status detected by said specific signal detection means to the transmission line determined as said spare transmission line by said discriminating means when said specific data is detected from the transmission line determined as said currently used transmission line by said discriminating means. - View Dependent Claims (5, 6, 7)
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8. A loop transmission system for effecting data communications among a plurality of stations, comprising:
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a plurality of stations including a supervising station and at least one terminal station; a pair of looped transmission lines, one of which is to operate as a current transmission line for carrying data communications between stations and the other of which is to operate as a spare transmission line not used for data communications; and respective switching means associated with each station and controlled thereby for connecting said plurality of stations in series in said current transmission line while connecting said spare transmission line to bypass said stations for data communications; said supervising station including specific signal generator means for generating a spare line designating code signal and first control means for controlling said switching means associated with said supervising station to connect said supervising station in series in said looped transmission line which is to operate as said current transmission line and to connect said specific signal generator means to said looped transmission line which is to operate as said spare transmission line so that said spare line designating code signal is carried thereby; said terminal station including specific signal detector means for detecting said spare line designating code signal on either one of said pair of looped transmission lines and second control means responsive to said specific signal detector means for controlling said switching means associated with that terminal station in series in the looped transmission line on which said spare line designating code signal is not detected. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification