DESCRIPTION
Field
[0001] The present invention relates to a branching
connector to be used for connecting a plurality of
communication apparatuses in the form of a daisy chain
connection.
Background
[0002] Conventionally, in a system including a plurality of communication apparatuses connected in the form of a daisy chain, the terminal stations are directly connected each other to ensure redundancy by means of loopback. In order to realize the loopback, interconnection lines for the loopback, which enable direct communication between the terminal stations of the daisy chain, need to be provided inside the communication apparatuses (see Patent Literature
1) •
[0003] Further, a RJ45 branching connector is known, which conforms to Registered jack RJ45 standard and has branching and consolidating functions for utilizing usually-unused terminals of a communication port. The RJ45 branching connector uses usually-unused terminals of a pre-branch port so as to enable communication for two ports, and so it can achieve branching two ports from one port
(see Patent Literature 2). The branching connector disclosed in Patent Literature 2 has a structure in that it includes two post-branch ports with respect to one pre-branch port.
Citation List

Patent Literature [0004]
Patent Literature 1: Japanese Patent Application Laid-open No. 2006-314098
Patent Literature 1: Japanese Patent Application Laid-open No . 2000-331758
Summary
Technical Problem
[0005] However, in the case of the conventional branching connector conforming to RJ45 standard, the pre-branch port is in a state where all of the terminals are used; but the two post-branch ports are in a state where usually-unused terminals are still left unused, which is the same as in an ordinary connector. Thus, this cannot be regarded as being sufficient in terms of effective use of the usually-unused terminals of the post-branch ports. [0006] The present invention has been made in view of the above, and an objective of the present invention is to provide a branching connector that makes good use of usually-unused terminals of the. post-branch ports.
Solution to Problem
[0007] In order to solve the problem and achieve the objective mentioned above, the present invention relates to a branching connector that includes: a pre-branch port to be connected to a first branching-connector compatible communication apparatus having a duplex communication function, which is a function whereby information is transmitted and received for two ports of a first channel and a second channel by using both of a usually-used terminal and a usually-unused terminal in a communication port; a first post-branch port to be connected to a second

branching-connector compatible communication apparatus having the duplex communication function; a second post-branch port to be connected to a third branching-connector compatible communication apparatus having the duplex communication function; a first channel wiring to connect a terminal of the.pre-branch port for the first channel and a usually-used terminal of the first post-branch port each other; a second channel wiring to connect a terminal of the pre-branch port for the second channel and a usually-used terminal of the second post-branch port each other; and a repeat wiring to connect a usually-unused terminal of the first post-branch port and a usually-unused terminal of the second post-branch port each other.
Advantageous Effects of Invention
[0008] The branching connector according to the present invention provides an effect capable of making good use of usually-unused terminals of the post-branch ports.
Brief Description of Drawings
[0009] FIG. 1 is a view illustrating a configuration of a branching connector according to a first embodiment of the present invention.
FIG. 2 is a view illustrating a configuration of a system connected in a daisy chain and in which the branching connector according to the first embodiment is used.
FIG. 3 is a view illustrating a state where a failure has occurred in a communication apparatus that is part of the system connected in a daisy chain and in which the branching connector according to the first embodiment is used.
FIG. 4 is a view illustrating a configuration of a

branching connector according to a second, embodiment of the present invention.
FIG. 5 is a view illustrating a configuration of a system connected in a daisy chain and in which the branching connector according to the second embodiment is used •..'■-.'
FIG. 6 is a top view of a switching plug that is used with a branching connector according to a third embodiment.
■FIG. 7 is a side view of the switching plug that is used with the branching connector according to the third embodiment.
FIG. 8 is a view illustrating a connection state between a pre-branch port, a first post-branch port, and a second post-branch port in the branching connector according to the third embodiment.
FIG. 9 is a view illustrating a connection state between the pre-branch port, the first post-branch port, and the second post-branch port in the branching connector according to the third embodiment.
Description of Embodiments
[0010] Exemplary embodiments of a branching connector according to the present invention are explained below in detail with reference to the accompanying drawings. The present invention is not limited to the following embodiments.
[0011] First Embodiment
FIG. 1 is a view illustrating a configuration of a branching connector according to a first embodiment of the present invention. The branching connector 101 is a connector that connects a branching-connector compatible communication apparatus 102, which is a first branching-connector compatible communication apparatus, to a

branching-connector compatible communication apparatus 120, which is a second branching-connector compatible communication apparatus, and to a branching-connector compatible communication apparatus 121, which is a third branching-connector compatible communication apparatus. Here, the branching-connector compatible communication apparatus is a communication apparatus that has a duplex communication function whereby it transmits and receives information for two ports by using both of a usually-used terminal and a usually-unused terminal in a communication port. Further, the usually-used terminal is a terminal prescribed to be used for communication in accordance with a given standard, and the usually-unused terminal is a terminal not prescribed to be used for communication in accordance with the given standard.
[0012] The branching connector 101 includes a pre-branch port 103 connected to the branching-connector compatible communication apparatus 102; a first post-branch port 107 connected to a plug 109 leading to the branching-connector compatible communication apparatus 120; a second post-branch port 108 connected to a plug 110 leading to the branching-connector compatible communication apparatus 121; a first channel wiring 104 connecting the pre-branch port 103 and the first post-branch port 107 each other; a second channel wiring 105 connecting the pre-branch port 103 and the second post-branch port 108 each other; and a repeat wiring 106 connecting the first post-branch port 107 and the second post-branch port 108 each other. [0013] The plug 109 is connected to the branching-connector compatible communication apparatus 120 by a communication cable 111. The plug 110 is connected to the branching-connector compatible communication apparatus 121 by a communication cable 112. Existing general components

may. be used for each of the plugs 109 and 110 and the communication cables 111 and 112.
[0014] The branching-connector compatible communication apparatus 102 is the branch source side communication apparatus for the branching inside the branching connector 101, and it has a function whereby it enables one port to transmit and receive information for two ports by using usually-unused terminals in the port.
[0015] The first channel wiring 104 connects a first channel side terminal 103a of the pre-branch port 103 to a first channel first terminal 107a, a first channel second terminal 107b, a first channel third terminal 107c, and a first channel fourth terminal 107d of the post-branch port
107. A second channel wiring 105 connects a second channel
side terminal 103b of the pre-branch port 103 to a second
channel first terminal 108a, a second channel second
terminal 108b, a second channel third terminal 108c, and a
second channel fourth terminal 108d of the post-branch port
108. 'In the first post-branch port 107, the terminals
usually used are the first channel first terminal 107a, the
first channel second terminal 107b, the first channel third
terminal 107c, and the first channel fourth terminal 107d,
which are connected to the first channel wiring 104. In
the second post-branch port 108, the terminals usually used
are the second channel first terminal 108a, the second
channel second terminal 108b, the second channel third
terminal 108c, and the second channel fourth terminal 108d,
which are connected to a second channel wiring 105.
[0016] The branching connector 101 rearranges the terminals of the pre-branch port 103, which correspond to two ports, back to an ordinary terminal arrangement, and it connects these terminals to the first post-branch port 107 and the second post-branch port 108. Specifically, the

first channel side terminal 103a of the pre-branch port 103 is connected by the first channel wiring 104 to the first channel first terminal 107a, the first channel second terminal 107b, the first channel third terminal 107c, and the first channel fourth terminal 107d, which are the usually-used terminals of the first post-branch port 107. Further, the second channel side terminal 103b of the pre-branch port 103 is connected by a second channel wiring 105 to the second channel first terminal 108a, the second channel second terminal 108b, the second channel third terminal 108c, and the second channel fourth terminal 108d, which are the usually-used terminals of the second post-branch port 108. Consequently, in the first post-branch port 107 and the second post-branch port 108, the usually-unused terminals become usable. The branching connector 101 uses these usually-unused terminals to establish a communication route between the first post-branch port 107 and the second post-branch port 108 through a repeat wiring 106.
[0017] Of the terminals of the first post-branch port 107 and the second post-branch port 108, a terminal for establishing the communication route between the first post-branch port 107 and the second post-branch port 108 is referred to as a "repeat terminal". Specifically, the repeat wiring 106 connects, respectively, a repeat first terminal 107e; a repeat second terminal 107f; a repeat third terminal 107g; and a repeat fourth terminal 107h of the first post-branch port 107 to a repeat first terminal 108e; a repeat second terminal 108f; a repeat third terminal 108g; and a repeat fourth terminal 108h of the second post-branch port 108. Thus, the repeat first terminal 107d, the repeat second terminal 107f, the repeat third terminal 107g, and the repeat fourth terminal 107h of

the first post-branch port 107 are connected by a repeat wiring 106 to the repeat first terminal 108e, the repeat second terminal 108f, the repeat third terminal 108g, and the repeat fourth terminal 108h of the second post-branch port 108, respectively.
[0018] FIG. 2 is a view illustrating a configuration of a system connected in a daisy chain and in which the branching connector according to the first embodiment is used. The system includes communication apparatuses 201, 202, 203, and 204, each of which has a function whereby they enable one port to transmit and receive information for two ports by using the usually-unused terminals in the port. In other words, each of the communication apparatuses 201, 202, 203, and 204 included in the system connected in a daisy chain is a branching-connector compatible communication apparatus that is connected to the pre-branch port 103 of the branching connector 101 and has a duplex communication function whereby it transmits and receives information, which corresponds to two ports, at one port. The pre-branch ports 103 of the branching connectors 101i and IOI2 are respectively connected to the communication apparatuses 202 and 203 of the communication apparatuses 201, 202, 203, and 204 included in the system, which are other than the communication apparatuses 201 and 204 positioned at the ends of the daisy chain. The second post-branch port 108 of the branching connector 101i and the first post-branch port 107 of the branching connector IOI2 are connected each other by a communication cable 208. [0019] The branching connectors 101i and IOI2 are distinguished from each other by attaching a subscript numeral to the reference symbol for the sake of convenience, but each of them has the same structure as the branching connector 101 illustrated in FIG. 1. Specifically, with a

focus on the branching connector 101i, the communication apparatus 202 functions as the first branching-connector compatible communication apparatus; one of the communication apparatuses 201 and 203 functions as the second branching-connector compatible communication apparatus; and the other of the communication apparatuses
201 and 203 functions as the third branching-connector compatible communication apparatus. Similarly, with a focus on the branching connector 1012, the communication apparatus 203 functions as the first branching-connector compatible communication apparatus; one of the communication apparatuses 202 and 204 functions as the second branching-connector compatible communication apparatus; and the other of the communication apparatuses
202 and 204 functions as the third branching-connector compatible communication apparatus.
[0020] The communication apparatus 201 is connected to the communication cable 207 by an ordinary connector included in the communication cable 207. The communication cable 207 includes two interconnection lines, which are an interconnection line 207a and an interconnection line 207b. By using not only the usually-used terminals but also the usually-unused terminals, the communication apparatus 201 is connected to the communication apparatus 202 by the interconnection line 207a, and it is connected to the communication apparatus 204 by the communication apparatus interconnection line 207b without using the communication apparatuses 202 and 203. Similarly, the communication apparatus 204 is connected to the communication cable 209 by an ordinary connector included in the communication cable 209. The communication cable 209 includes two interconnection lines, which are an interconnection line 209a and an interconnection line 209b. By using not only

the usually-used terminals but also the usually-unused terminals, the communication apparatus 204 is connected to the communication apparatus 203 by the interconnection line 209a, and it is connected to the communication apparatus 201 by the communication apparatus interconnection line 209b without using the communication apparatuses 202 and 203. The usually-used terminals of the second post-branch port 108 of the branching connector 101i are connected to the usually-used terminals of the first post-branch port 107 of the branching connector 1012 by an interconnection line 208a in the communication cable 208. The usually-unused terminals of the second post-branch port 108 of the branching connector 101i are connected to the usually-unused terminals of the first post-branch port 107 of the branching connector IOI2 by an interconnection line 208b in the communication cable 208. Note that the interconnection lines connecting the communication apparatus 201 and the communication apparatus 204 each other without passing through the communication apparatuses 202 and 203 are described later.
[0021] In the branching connector 101i, the usually-used terminals of the first post-branch port 107 are connected to a terminal of the pre-branch port 103 by the first channel wiring 104, and the usually-used terminals of the second post-branch port 108 are connected to a terminal of the pre-branch port 103 by a second channel wiring. Accordingly, information sent from the communication . apparatus 201 through the interconnection line 207a and information sent from the communication apparatus 203 through the interconnection line 208a are transmitted to the communication apparatus 202. Furthermore, information transmitted by the repeat terminals of the first post-branch port 107 and the second post-branch port 108 is not

relayed by the communication apparatus 202 but is sent and received by the repeat wiring 106 between the first post-branch port 107 and the second post-branch port 108. [0022] In the branching connector IOI2, the usually-used terminals of the first post-branch port 107 are connected to a terminal of the pre-branch port 103 by the first channel wiring 104; and the usually-used terminals of the second post-branch port 108 are connected to a terminal of the pre-branch port 103 by a second channel wiring. Accordingly, information sent from the communication apparatus 202 through the interconnection line 208a and information sent from the communication apparatus 204 through the interconnection line 209a are transmitted to the communication apparatus 203. Furthermore, information transmitted by the repeat terminals of the first post-branch port 107 and the second post-branch port 108 is not relayed by the communication apparatus 203 but is sent and received by a repeat wiring 106 between the first post-branch port 107 and the second post-branch port 108. [0023] As described above, the interconnection line 207a of the communication cable 207, the interconnection line 208a of the communication cable 208, and the interconnection line 209a of the communication cable 209 form interconnection lines for transmitting information exchanged between adjacent communication apparatuses. Furthermore, the interconnection line 207b of the communication cable 207, the interconnection line 208b of the communication cable 208, and the interconnection line 209b of the communication cable 209 form interconnection lines for respectively connecting the communication apparatus 201 and the communication apparatus 204 without passing through the communication apparatuses 202 and 203. [0024] FIG. 3 is a view illustrating a state where a

failure has occurred in a communication apparatus that is part of the system that has a daisy chain connection and in which the branching connector according to the first embodiment is used. FIG. 3 illustrates, by annotating the communication apparatus 203 with an "x", that a failure has occurred at the communication apparatus 203. - When a failure has occurred in the communication apparatus 203 that is part of the system connected in a daisy chain and therefore the communication is unable, communication between the communication apparatus 202 and the communication apparatus 203 and the communication between the communication apparatus 203 and the communication apparatus 204 is cut. However, the repeat wiring 106 in the branching connector 1012 connected to the communication apparatus 203 ensures the communication continued between the communication apparatus 201 and the communication apparatus 204. This enables communication, with the exception of the communication apparatus 203, to be sustained between the communication apparatus 201, the communication apparatus 202, and the communication apparatus 204.
[0025] To the contrary, according to the conventional branching connector, when a failure has occurred at a communication apparatus connected to the pre-branch port, communication cannot be sustained between two communication apparatuses connected to the two post-branch ports, as in an ordinary system with daisy chain connection. Accordingly, in a system including communication apparatuses that are connected in the form of a daisy chain by using a conventional branching connector, when a failure has occurred at a communication apparatus inside the system, the system is cut in half at the failed communication apparatus.

[0026] Further, conventionally, a method is used for enabling redundancy by means of loopback by directly connecting the terminal stations to each other in a system formed in a daisy chain connection using cables of category 5. However, a problem occurs in the technique that the interconnection lines dedicatedly used for the loopback need to be provided inside of all the communication apparatuses in the system, and so the communication apparatuses must have complicated inner structures.
[0027] In the branching connector according to the first embodiment, the usually-unused terminals of the two post-branch ports are connected each other by a repeat wiring so as to establish a communication route without passing through the communication apparatuses connected to the pre-branch port. Accordingly, a direct communication interconnection line is established between the terminal stations in a system with daisy chain connection, whereby it enables redundancy by means of loopback in the system without adding any function to the communication apparatuses.
[0028] Further, the branching connector, which is independent of the communication apparatus, includes a repeat wiring for connecting the post-branch ports each other. Accordingly, if a system is not formed with daisy chain connection, a communication apparatus that has no duplex communication function can be used in the system. This enables to reduce the costs for the constructions of the communication apparatuses.
[0029] As described above, the branching connector according to the first embodiment includes a repeat wiring that connects the usually-unused terminals of the first post-branch port and the usually-unused terminals of the second post-branch port each other. Accordingly, when the

communication apparatuses are connected in the form of a daisy chain by using the branching connector according to the first embodiment, there is no need to provide interconnection lines dedicatedly used for the loopback inside the communication apparatuses. Further, even if a failure has occurred at a communication apparatus positioned at the middle inside the system with daisy chain connection, communication can be sustained between the communication apparatuses having no failure. [0030] Second Embodiment
FIG. 4 is a view illustrating a configuration of a branching connector according to a second embodiment of the present invention. In the branching connector 301 according to the second embodiment, a repeat first terminal 306e, a repeat second terminal 306f, a repeat third terminal 306g, and a repeat fourth terminal 306h of a first post-branch port 306 are connected to a second channel first terminal 307a, a second channel second terminal 307b, a second channel third terminal 307c, and a second channel fourth terminal 307d of a second post-branch port 307. A pre-branch port 303 and first channel wiring 304 are respectively the same as the pre-branch port 103 and the first channel wiring 104 of the branching connector 101 according to the first embodiment. Specifically, the first channel wiring 304 connects a first channel side terminal 303a of the pre-branch port 303 to a first channel first terminal 306a, a first channel second terminal 306b, a first channel third terminal 306c, and a first channel fourth terminal 306d of the first post-branch port 306. [0031] A second channel side terminal 303b of the pre-branch port 303 is not connected to either of the first post-branch port 306 and the second post-branch port 307. Further, the second post-branch port 307 is not equipped

with any repeat terminal, and so its terminals other than the second channel first terminal 307a, the second channel second terminal 307b, the second channel third terminal 307c, and the second channel fourth terminal 307d are set as unused terminals that are usually unused. [0032] The pre-branch port 303 is connected to a branching-connector compatible communication apparatus 302 having a duplex communication function.
[0033] The first post-branch port 306 is connected to a branching-connector compatible communication apparatus 320 via a plug 308 and a communication cable 310. [0034] The second post-branch port 307 is connected to a communication port 313 of a communication apparatus that has no duplex communication function, via a plug 309, a communication cable 311, and a plug 312. In the communication port 313 of the communication apparatus that has no duplex communication function, a first terminal 313a, a second terminal 313b, a third terminal 313c, and a fourth terminal 313d are usually-used terminals; and a fifth terminal 313e, a sixth terminal 313f, a seventh terminal 313g, and an eighth terminal 313h are usually-unused terminals, which are set as unused terminals. [0035] The branching connector 301 uses the usually-unused terminals to reallocates data, which has been transmitted from the branching-connector compatible communication apparatus 320, to the usually-used terminals by using a repeat wiring 305. Accordingly, the communication port 313 of the communication apparatus that has no duplex communication function, i.e., having no function to use a usually-unused terminal, can be connected to the second post-branch port 307.
[0036] FIG. 5 is a view illustrating a configuration of a system connected in a daisy chain and in which the

branching connector according to the second embodiment is used. Each of communication apparatuses 401, 402, 403, and 404 has a function whereby it enables one single port to communicate information for two ports by using usually-unused terminals.
[0037] The.pre-branch ports 103 of branching connectors IOI3 and IOI4 are respectively connected to the communication apparatuses 402 and 403 of the communication apparatuses 401, 402, 403, and 404 included in the system, which are other than the communication apparatuses 401 and 404 positioned at the ends of the daisy chain. Each of the branching connectors 1013 and 1014 connected to the communication apparatuses 402 and 403 has the same structure as the branching connector 101 according to the first embodiment. The second post-branch port 108 of the branching connector IOI3 and the first post-branch port 107 of the branching connector IOI4 are connected each other by a communication cable 410.
[0038] The pre-branch ports 303 of branching connectors 301i and 3012 are respectively connected to the communication apparatuses 401 and 404 of the communication apparatuses 401, 402, 403, and 404 included in the system,
o
which are positioned at the ends of the daisy chain. Each of the branching connectors 301i and 3OI2 connected to the communication apparatuses 401 and 404 has the same structure as the branching connector 301.
[0039] The first post-branch port 306 of the branching connector 301i and the first post-branch port 107 of the branching connector IOI3 are connected each other by a communication cable 409. The first post-branch port 306 of the branching connector 3OI2 and the second post-branch port 108 of the branching connector IOI4 are connected each other by a communication cable 411.

[0040] As illustrated in FIG. 5, the branching connectors 301i and 3012 according to the second embodiment are used in a state connected to the communication. apparatuses 401 and 404, which are positioned at the ends of the system and are connected in the form of a daisy chain by the branching connectors IOI3 and 1014 according to the first embodiment. The branching connectors 301i and 3012 are not solely used, but are used with others.
[0041] Note that with a focus on the branching connector 301i, the communication apparatus 401 serves as the first branching-connector compatible communication apparatus; and the communication apparatus 402 serves as the second branching-connector compatible communication apparatus. Similarly, with a focus on the branching connector 3012, the communication apparatus 404 serves as the first branching-connector compatible communication apparatus; and the communication apparatus 403 serves as the second branching-connector compatible communication apparatus. [0042] The communication cable 409 includes an interconnection line 409a for communication between the communication apparatus 401 and the communication apparatus 402; and an interconnection line 409b for connecting the communication apparatus 401 and the communication apparatus 404 each other without passing through the communication apparatuses 402 and 403. Similarly, the communication cable 410 includes an interconnection line 410a for communication between the communication apparatus 402 and the communication apparatus 403; and an interconnection line 410b for connecting the communication apparatus 401 and the communication apparatus 404 each other without passing through the communication apparatuses 402 and 403. Similarly, the communication cable 411 includes an interconnection line 411a for communication between the

communication apparatus 4 03 and the communication apparatus 404; and an interconnection line 411b for connecting the communication apparatus 401 and the communication apparatus 404 each other without passing through the communication apparatuses 402 and 403.
[0043] The usually-used terminals of the first post-branch port 306 of the branching connector 301i are connected to the usually-used terminals of the first post-branch port 107 of the branching connector IOI3 by the interconnection line 409a in the communication cable 409. The usually-unused terminals of the first post-branch port 306 of the branching connector 301i are connected to the usually-unused terminal of the first post-branch port 107 of the branching connector IOI3 by the interconnection line 409b in the communication cable 409.
[0044] The usually-used terminals of the first post-branch port 306' of the branching connector 3012 are connected to the usually-used terminals of the second post-branch port 108 of the branching connector 1014 by the interconnection line 411a in the communication cable 411. The usually-unused terminals of the first post-branch port 306 of the branching connector 3OI2 are connected to the usually-unused terminal of the second post-branch port 108 of the branching connector 1014 by the interconnection line 411b in the communication cable 411.
[0045] The usually-used terminals of the second post-branch port 108 of the branching connector IOI3 are connected to the usually-used terminals of the first post-branch port 107 of the branching connector 1014 by the interconnection line 410a in the communication cable 410. The usually-unused terminals of the second post-branch port 108 of the branching connector IOI3 are connected to the usually-unused terminals of the first post-branch port 107

of the branching connector 1014 by the interconnection line 410b in the communication cable 410.
[0046] In the branching connector IOI3, the usually-used terminals of the first post-branch port 107 are connected to a terminal of the pre-branch port 103 by the first channel wiring 104; and the usually-used terminals of the second post-branch port 108 are connected to a terminal of the pre-branch port 103 by a second channel wiring 105. Accordingly, information sent from the communication apparatus 401 through the interconnection line 409a and information sent from the communication apparatus 403 through the interconnection line 410a is transmitted to the communication apparatus 402. On the other hand, information transmitted by the repeat terminals of the first post-branch port 107 and the second post-branch port 108 is not relayed by the communication apparatus 402, but is sent and received by a repeat wiring 106 between the first post-branch port 107 and the second post-branch port -108. [0047] In the branching connector IOI4, the usually-used terminals of the first post-branch port 107 are connected to a terminal of the pre-branch port 103 by the first channel wiring 104; and the usually-used terminals of the second post-branch port 108 are connected to a terminal of the pre-branch port 103 by a second channel wiring 105. Accordingly, information sent from the communication apparatus 402 through the interconnection line 410a and information sent from the communication apparatus 404 through the interconnection line 411a is transmitted to the communication apparatus 403. On the other hand, information transmitted by the repeat terminals of the first post-branch port 107 and the second post-branch port 108 is not relayed by the communication apparatus 403, but

is sent and received by a repeat wiring 106 between the first post-branch port 107 and the second post-branch port 108.
[0048] As described above, the interconnection line 409a of the communication cable 409, the interconnection line 410a of the communication cable 410, and the interconnection line 411a of the communication cable 411 form interconnection lines for transmitting information exchanged between adjacent communication apparatuses. On the other hand, the interconnection line 409b of the communication cable 409, the interconnection line 410b of the communication cable 410, and the interconnection line 411b of the communication cable 411 form interconnection lines for directly connecting a communication apparatus 412 having no duplex communication function and a communication apparatus 413 having no duplex communication function each other.
[0049] Since the branching connectors 301i and 3012 are connected to the communication apparatuses 401 and 404 positioned at the ends of the system, the communication apparatuses 412 and 413 having no duplex communication function can be respectively connected to the second post-branch ports 307 of the branching connectors 301i and 3OI2. In the system, interconnection lines can be constructed for directly connecting the communication apparatuses 412 and 413 having no duplex communication function each other through repeat wirings 305 and 106 in the branching connectors 301i, IOI3, IOI4, and 3OI2.
[0050] Because the conventional branching connector is intended to provide redundancy, a communication apparatus unrelated to the system cannot be connected to perform communication. Thus, the conventional branching connector lacks expandability.

[0051] On the other hand, in the case of the branching connector according to the second embodiment, in a case where branching connectors of this type are connected to the communication apparatuses positioned at the ends of the system with daisy chain connection, communication apparatuses having no duplex communication function can be respectively connected to the communication apparatuses at the opposite ends of the system so as to establish individualized interconnection lines between the communication apparatuses having no duplex communication function. Consequently, even if communication apparatuses having no duplex communication function are used as the terminal stations of a system formed with daisy chain connection, it is possible to ensure the communication performance without being affected by communication apparatuses positioned at the middle of the system. [0052] Third Embodiment
FIG. 6 is a top view of a switching plug that is used with a branching connector according to a third embodiment. FIG. 7 is a side view of the switching plug that is used with the branching connector according to the third embodiment. The switching plug 502 includes: a cable 501 serving as wiring to be connected to the pre-branch port and the first post-branch port; an insulating portion 503 to be inserted into the second post-branch port; first terminals 504a arranged on the upper surface 503a of the insulating portion 503; and second terminals 504b arranged on the lower surface 503b of the insulating portion 503. That is, the first terminals 504a and the second terminals 504b are provided back to back. The number of first terminals 504a arranged on the upper surface 503a of the insulating portion 503 is equal to the number of second terminals 504b arranged on the lower surface 503b. However,

the first terminals 504a and the second terminals 504b differ from each other in terms of connection to the terminals of the pre-branch port and the first post-branch port.
[0053] When the insulating portion 503 is inserted into the second post-branch port, the first terminals 504a arranged on the upper surface 503a of the insulating portion 503 or the second terminals 504b arranged on the lower surface 503b are connected to terminals of the second post-branch port. Accordingly, depending on which orientation is used to insert the insulating portion 503 into the second post-branch port, the connection states of the pre-branch port and the first post-branch port with respect to the second post-branch port are switched. Here, the orientation in which the first terminals 504a come into contact with terminals of the second post-branch port is referred to as "first orientation"; and the orientation in which the second terminals 504b come into contact with terminals of the second post-branch port is referred to as "second orientation".
[0054] In this respect, an assumption is made as follows: When the first terminals 504a on the upper surface 503a side of the insulating portion 503 are connected to terminals of the second post-branch port, there is provided a connection state the same as that of the branching connector 101 according to the first embodiment. When the second terminals 504b on the lower surface 503b side of the insulating portion 503 are connected to terminals of the second post-branch port, there is provided a connection state the same as that of the branching connector 301 according to the second embodiment. [0055] FIG. 8 is a view illustrating a connection state

between a pre-branch port, a first post-branch port, and a second post-branch port in the branching connector according to the third embodiment. FIG. 8 illustrates a state where the first terminals 504a on the upper surface 503a side of the insulating portion 503 are connected to terminals of the second post-branch port 603. The usually-unused terminals of the first post-branch port 602 of the branching connector 600 according to the third embodiment serve as repeat channels and are connected to the terminals of the second post-branch port 603. Since the first terminals 504a on the upper surface 503a side of the insulating portion 503 are connected to the terminals of the second post-branch port 603, the repeat terminals of the first post-branch port 602 are connected to the repeat terminals of the second post-branch port. Accordingly, in the branching connector 600, the pre-branch port 601 and the first post-branch port 602 are connected each other by a first channel wiring, and the pre-branch port 601 and the second post-branch port 603 are connected each other by a second channel wiring. Further, the first post-branch port 602 and the second post-branch port 603 are connected each other by a repeat wiring.
[0056] The connection state illustrated in FIG. 8 is such that the first terminals 504a arranged on the upper surface 503a side of the insulating portion 503 are connected to terminals of the second post-branch port 603; and the connection state of the pre-branch port 601 and the first post-branch port 602 with respect to the second post-branch port 603 is the same as the branching connector 101 according to the first embodiment.
[0057] FIG. 9 is a view illustrating a connection state between the pre-branch port, the first post-branch port, and the second post-branch port in the branching connector

according to the third embodiment. FIG. 9 illustrates a state where the second terminals 504b on the lower surface 503b side of the insulating portion 503 are connected to terminals of the second post-branch port 603. The usually-unused terminals of the first post-branch port 602 of the branching connector 600 serve as repeat terminals. Since the second terminals 504b on the lower surface 503b side of the insulating portion 503 are connected to the terminals of the second post-branch port 603/ the repeat terminals of the first post-branch port 602 are connected to the usually-used terminals of the second post-branch port. Accordingly, the pre-branch port 601 and the first post-branch port 602 are connected each other' by the first channel; and the first post-branch port 602 and the second post-branch port 603 are connected each other in a state where their arrangement has been converted such that signals transmitted and received by using the usually-unused terminals in the first post-branch port 602 are transmitted and received by using the usually-used terminals in the second post-branch port 603. [0058] A branching connector has been known in which it uses a slide component to alter the connection between internal terminals. However, the branching connector has a structure with a mechanically movable part present therein as the slide component, and so it ends up having a larger size.
[0059] In the case of the branching connector according to the third embodiment, the wiring state inside the branching connector can be set different between a case where it is applied to an intermediate station in a system formed with daisy chain connection and a case where it is applied to a terminal station in the system. Since the switching of the wiring state is performed by changing the

orientation of the switching plug, there is no need to provide a mechanism including a movable part, such as a slide switch. Accordingly, the branching connector according to the third embodiment can be made smaller, as compared with a case where a movable part is provided. [0060] Note that, in the explanation described above, the number of first terminals 504a and the number of second terminals 504b are equal to each other, but the second terminals 504b can be provided only in the number of those to be connected to the usually-used terminals of the second post-branch port 603. In this case, since the number of first terminals 504a and the number of second terminals 504b are different from each other, it becomes easier to identify the upper and lower sides of the switching plug 502. This can help to prevent the switching plug 502 from being inserted into the second post-branch port 603, with a different orientation other than the intended one. [0061] The configurations illustrated in the above embodiments.are mere examples of the contents of the present invention, and they may be combined with other known techniques. Further, the configurations may be partly omitted or changed without departing from the spirit of the present invention.
Reference Signs List
[0062] 101, 101i, 1012, 1013, IOI4, 301, 3011, 3012, 320, 600 branching connector, 102, 302, 120, 121 branching-connector compatible communication apparatus, 103, 303, 601 pre-branch port, 103a, 303a first channel side terminal, 103b, 303b second channel side terminal, 104, 304 first channel wiring, 105 a second channel wiring, 106, 305 a repeat wiring, 107, 306, 602 first post-branch port, 107a, 306a first channel first terminal, 107b, 306b first

channel second terminal, 107c, 306c first channel third terminal, 107d, 306d first channel fourth terminal, 107e, 108e, 306e repeat first terminal, 107f, 108f, 306f repeat second terminal, 107g, 108g, 306g repeat third terminal, 107h, 108h, 306h repeat fourth terminal, 108, 307, 603 second post-branch port, 108a, 307a second channel first terminal, 108b, 307b second channel second terminal, 108c, 307c second channel third terminal, 108d, 307d second channel fourth terminal, 109, 110, 308, 309, 312 plug, 111, 112, 207, 208, 209, 310, 311, 409, 410, 411 communication cable, 201, 202, 203, 204, 401, 402, 403, 404
communication apparatus, 207a, 207b, 208a, 208b, 209a, 209b, 409a, 409b, 410a, 410b, 411a, 411b interconnection line, 313 communication port, 313a first terminal, 313b second terminal, 313c third terminal, 313d fourth terminal, 313e fifth terminal, 313f sixth terminal, 313g seventh terminal, 313h eighth terminal, 412, 413 communication apparatus that has no duplex communication function, 501 cable, 502 switching plug, 503 insulating portion, 503a upper surface, 503b lower surface, 504a first terminal, 504b second terminal.

We Claim :
1. A branching connector comprising:
a pre-branch port to be connected to a first branching-connector compatible communication apparatus having a duplex communication function, which is a function whereby information is transmitted and received for two ports of a first channel and a second channel by using both of a usually-used terminal and a usually-unused terminal in a communication port;
a first post-branch port to be connected to a second branching-connector compatible communication apparatus having the duplex communication function;
a second post-branch port to be connected to a third branching-connector compatible communication apparatus having the duplex communication function;
a first channel wiring to connect a terminal of the pre-branch port for the first channel and a usually-used terminal of the first post-branch port each other;
a second channel wiring to connect a terminal of the pre-branch port for the second channel and a usually-used terminal of the second post-branch port each other; and
a repeat wiring to connect a usually-unused terminal of the first post-branch port and a usually-unused terminal of the second post-branch port each other.
2. A branching connector comprising:
a pre-branch port to be connected to a first branching-connector compatible communication apparatus having a duplex communication function, which is a function whereby information is transmitted and received for two ports of a first channel and a second channel by using both of a usually-used terminal and a usually-unused terminal in a communication port;

a first post-branch port to be connected to a second branching-connector compatible communication apparatus having the duplex communication function;
a second post-branch port to be connected to a communication apparatus not having the duplex communication function;
a first channel wiring to connect a terminal of the pre-branch port for the first channel and a usually-used terminal of the first post-branch port each other; and
a repeat wiring to connect a usually-unused terminal of the first post-branch port and a usually-used terminal of the second post-branch port each other.
3. A branching connector comprising:
a pre-branch port to be connected to a first branching-connector compatible communication apparatus having a duplex communication function, which is a function whereby information is transmitted and received for two ports of a first channel and a second channel by using both of a usually-used terminal and a usually-unused terminal in a communication port;
a first post-branch port to be connected to a second branching-connector compatible communication apparatus having the duplex communication function;
a second post-branch port to be connected
to a third branching-connector compatible communication apparatus having the duplex communication function or
to a communication apparatus not having the duplex communication function; and
a switching plug to include wiring to lead to terminals of the pre-branch port and the first post-branch port, the switching plug being attachable to the second

post-branch port in a first orientation or second orientation, wherein,
when the switching plug is attached to the second post-branch port in the first orientation, the wiring forms
a first channel wiring that connects a terminal of the pre-branch port for the first channel and a usually-used terminal of the first post-branch port each other,
a second channel wiring that connects a terminal of the pre-branch port for the second channel and a usually-used terminal of the second post-branch port each other, and
a first repeat wiring that connects a usually-unused terminal of the first post-branch port and a usually-unused terminal of the second post-branch port each other, and
when the switching plug is attached to the second post-branch port in the second orientation, the wiring forms
the first channel wiring and
a second repeat wiring that connects a usually-unused terminal of the first post-branch port and a usually-used terminal of the second post-branch port each other.
4. The branching connector according to claim 3, wherein the switching plug includes
a first terminal that is electrically connected to a terminal of the second post-branch port when the switching plug is attached to the second post-branch port in the first orientation, and
a second terminal that is electrically connected to a terminal of the second post-branch port when the switching plug is attached to the second post-branch port

in the second orientation, and
wherein the first terminal and the second terminal are provided back to back.