Duplex system of transmission lines in a loop network

Claim 2

A duplex system of transmission lines in a loop network in which a plurality of communication nodes each having data transmission/receive means are connected through duplex loop transmission lines for transmitting data in reverse directions, each of said communication nodes comprising: loop back means for effecting a loop back operation in response to a predetermined state of signals received from two directions of said duplex loop transmission lines; and return indication means for adding, to an output signal, a return indication that a received signal was returned when said received signal could not be passed through the node; whereby, in response to the signal received from the two directions, each of said communi­cation nodes autonomously executes or releases the loop back operation.

Claim 3

A duplex system according to claim 1, wherein one of said communication nodes is a supervisory node having an active/standby indication means for adding, to the send signals to be transferred to the two directions of said duplex transmission lines, active/standby indications that each of said two directions is an active or standby route.

Claim 4

A duplex system according to claim 1, wherein when said two directions are assumed to be an #0 route and a #1 route, respectively, each of said communication nodes has a switching means for switching, in response to active/standby indications of the signals received from said #0 route and said #1 route, between the two directions of the duplex transmission lines.

Claim 5

A duplex system according to claim 2, wherein said two directions are assumed to be an #0 route and a #1 route, respectively, said supervisory node having a switching means for switching, in response to the active/standby indications of the signals received from said #0 route and said #1 route, between the two directions of the duplex transmission lines.

Claim 6

A duplex system according to claim 1, wherein said two directions are assumed to be an #0 route and a #1 route, respectively; each of said communication nodes having: a switching means for switching the connection from the #0 route to the #1 route and from the #1 route to the #0 route; and a control means for controlling said switching means based on the active/standby indications in the signals received from said #0 route and #1 route, respectively.

Claim 7

A duplex system according to claim 5, wherein: said return indication means in each of said communication nodes has a means for adding said return indication to a returned signal when it is a result of a control by said switching means.

Claim 8

A duplex system according to claim 6, wherein: said control means in each of said communication nodes has a data table for storing a control pattern for driving said switching means; said control pattern including four kinds of receiving patterns consisting of active/standby and active return/standby return in the signal received from said #0 route; and said control pattern including four kinds of receiving patterns consisting of active/standby and active-return/standby-return in the signal received from said #1 route.

Claim 9

A duplex system according to claim 7, wherein: each of said communication nodes has a loop back releasing means for autonomously releasing said loop back operation when said node receives a predetermined pattern in the signals received from the two directions.

Claim 10

A duplex system according to claim 1, wherein: said communication nodes comprise a supervisory node and subsidiary nodes, said supervisory node has an active/standby indication means for adding, to the output signals to be transferred to the two directions of said duplex transmission lines, active/standby indications that each of said two directions is an active or standby route; and when said two directions are assumed to be an #0 route and a #1 route, respectively, each of said terminal nodes has a switching means for switching, in response to the active/standby indications of the signals received from said #0 route and said #1 route, between the two directions of the duplex transmission lines.

Claim 11

A duplex system according to claim 9, wherein: said supervisory node has a switching means for switching, in response to the active/standby indications of the signals received from said #0 route and said #1 route, between the two directions of the duplex transmission lines; and each of said terminal nodes has a switching means for switching the connection from the #0 route to the #1 route and from the #1 route to the #0 route; and control means for controlling said switching means based on the active/standby indications in the signals received from said #0 route and #1 route, respectively.

Claim 12

A duplex system according to claim 10, wherein: each of said terminal nodes has a means for adding said return indication to a returned signal when it is a result of a control by said switching means; and said control pattern including four kinds of receiving patterns supervisory node respectively have data tables for storing a control pattern for driving said switching means; said control pattern including four kinds of receiving patterns consisting of active/standby and active return/standby return in the signal received from said #0 route; and said control pattern including four kinds of receiving patterns consisting of active/standby and active return/standby-return in the signal received from said #1 route.

Claim 13

A duplex system according to claim 10, wherein: each of said communication nodes has a loop back releasing means for automatically releasing said loop back operation when a node under a loop back operation in each of said terminal nodes or said super­visory node receives a predetermined pattern in the signals received from two directions.

Claim 14

In a duplex system of transmission lines in a loop network in which a plurality of communication nodes having data transmission/receiving means are connected by duplex loop transmission lines for transmitting data in reverse directions, a transmission line duplex system in a loop network characterized by; inserting control data indicating the connecting state of said each transmission line to each frame transmitted through said each transmission line, and having, in said each communication node, control data separating means for detecting and separating, at a predetermined time interval, control data inserted to said each frame which is input from said each transmission lines; transmission line switch control means for switching the connecting state between each input/output of said each transmission line and the input/output of said data transmission/receiving means, based on the control data separated by said each control data separating means; and control data multiplexing means for multiplexing new control data on said each frame to be transmitted to said each transmission line, based on the connection state; whereby, by the dis­tributed control at said each communication node, a control corresponding to the change of condition of the network is carried out.

Claim 15

In a duplex system of transmission lines in a loop network in which a plurality of communication nodes having data transmission/receiving means are connected by duplex loop transmission lines for transmitting data in reverse directions, a transmission line duplex system in a loop network characterized by; inserting control data indicating the connecting state of said each transmission line to each frame transmitted through said each transmission line, and having, in said each communication node, control data separating means for detecting and separating, at a predetermined time interval, control data inserted to said each frame which is input from said each transmission lines; transmission line switch control means for switching the connecting state between each input/output of said each transmission line and the input/output of said data transmission/receiving means, based on the control data separated by said each control data separating means; and control data multiplexing means for multiplexing new control data on said each frame to be transmitted to said each transmission line, based on the connection state; whereby, by the dis­tributed control at said each communication node, a control corresponding to the change of condition of the network is carried out.

Claim 16

A duplex system according to claim 13, wherein when said two directions are assumed to be an #0 route and a #1 route, respectively, each of said communication nodes has a switching means for switching, in response to the active/standby indications of the signals received from said #0 route and said #1 route, between the two directions of the duplex transmission lines.

Claim 17

A duplex system according to claim 14, wherein said two directions are assumed to be an #0 rout and a #1 rout, respectively, said supervisory node having a switching means for switching, in response to the active/standby indications of the signals received from said #0 route and said #1 route, between the two directions of the duplex transmission lines.

Claim 18

A duplex system according to claim 14, wherein said two directions are assumed to be an #0 route and a #1 route, respectively; each of said communication nodes having: a switching means for switching the connection from the #0 route to the #1 route and from the #1 route to the #0 route; and a control means for controlling said switching means based on the active/standby indications in the signals received from said #0 route and #1 route respectively.

Claim 19

A duplex system according to claim 16, wherein: said return indication means in each of said communication nodes has a means for adding said return indication to a returned signal when it is a result of a control by said switching means.

Claim 20

A duplex system according to claim 17, wherein: said control means in each of said communication nodes has a data table for storing a control pattern for driving said switching means; said control pattern including four kinds of receiving patterns consisting of active/standby and active-return/standby-return in the signal received from said #0 route; and said control pattern including four kinds of receiving patterns consisting of active/standby and active return/standby return in the signal received from said #1 route.

Claim 21

A duplex system according to claim 18, wherein: each of said communication nodes has a loop back releasing means for automatically releasing said loop back operation when said node receives a predetermined pattern in the received signals from two directions.

Claim 22

A duplex system according to claim 14, wherein: said communication nodes comprise a supervisory node and terminal nodes, said supervisory node has an active/standby indication means for adding, to the send signals to be transferred to the two directions of said duplex transmission lines, active/standby indications that each of said two directions is an active or standby route; and when said two directions are assumed to be an #0 route and a #1 route, respectively, each of said terminal nodes has a switching means for switching, in response to the active/standby indications of the signals received from said #0 route and said #1 route, between the two directions of the duplex transmission lines.

Claim 23

A duplex system according to claim 20, wherein: said supervisory node has a switching means for switching, in response to the active/standby indications of the signals received from said #0 route and said #1 route, between the two directions of the duplex transmission lines; and each of said terminal nodes has a switching means for switching the connection from the #0 route to the #1 route and from. the #1 route to the #0 route; and a control means for controlling said switching means based on the active/standby indications in the signals received from said #0 route and #1 route respectively.

Claim 24

A duplex system according to claim 21, wherein: each of said terminal nodes has a means for adding said return indication to a returned signal when it is a result of a control by said switching means; and said control means in each of said terminal nodes and said supervisory node, respectively, have data tables for storing a control pattern for driving said switching means; said control pattern including four kinds of receiving patterns consisting of active/standby and active-return/standby-return in the signal received from said #0 route; and said control pattern including four kinds of receiving patterns consisting of active/standby and active-return/standby-return in the signal received from said #1 route.

Claim 25

A duplex system according to claim 22, wherein: each of said communication nodes has a loop back releasing means for automatically releasing said loop back operation when a node under the loop back operation in each of said terminal nodes or said super­visory node receives a predetermined pattern in the signals received from two directions.