Multiplex communications – Fault recovery – Bypass an inoperative station
Reexamination Certificate
1997-04-21
2001-05-29
Patel, Ajit (Department: 2661)
Multiplex communications
Fault recovery
Bypass an inoperative station
Reexamination Certificate
active
06240064
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to ring structure 1:N duplex communication equipment in which a host device and a plurality of slave devices are interconnected in a ring form in two ways, and more particularly to 1:N duplex communication equipment for transmitting data from a specified slave device in response to multi-address data which has been sent from the host device.
Referring to
FIG. 2
, there is shown 1:N duplex communication equipment, which has conventionally been used. Paths
1
to n respectively interconnect a host device
21
and a plurality of slave devices
22
-
1
to
22
-n.
The host device
21
includes a path distributing part
23
for distributing the plurality of paths
1
to n, a plurality of path selecting parts
25
-
1
to
25
-n for selecting paths from the slave devices
22
-
1
to
22
-n of two-way transmission lines and a received data selecting part
26
for selecting effective received data upon receiving data from the selected plurality of paths. These parts are arranged for transmitting multi-address data to the plurality of slave devices
22
-
1
to
22
-n. The plurality of slave devices
22
-
1
to
22
-n include path selecting parts
27
-
1
to
27
-n for selecting paths from the two-way transmission lines and path transmitting parts
24
-
1
to
24
-n for distributing received data to the paths of the two-way transmission lines.
The host device
21
transmits data having identical information through the plurality of paths
1
to n. The slave devices receive the data transmitted from the host device through the paths selected by the path selecting parts
27
-
1
to
27
-n. When there is data to be transmitted, each of the slave devices
22
-
1
to
22
-n transmits a data effective signal together with the data to be transmitted through the path. The paths from the slave devices
22
-
1
to
22
-n are respectively distributed to the two-way transmission lines in the path transmitting parts
24
-
1
to
24
-n.
In the host device, the paths
1
to n from the two-way transmission lines are respectively selected by the path selecting parts
25
-
1
to
25
-n and received data is selected from the selected path by the received data selecting part. The host device
21
and the path selecting parts
27
-
1
to
27
-n of the slave devices
22
-
1
to
22
-n operate so as to select a normal transmission line when one transmission line fails.
The conventional 1:N duplex communication equipment described above with reference to
FIG. 2
is disadvantageous in that the same number of paths as that of slave devices is needed.
SUMMARY OF THE INVENTION
A purpose of the present invention is to provide ring structure 1:N duplex communication equipment, whereby 1:N bi-directional communication can be performed with a smaller number of paths.
The purpose of the present invention is achieved by ring structure 1:N duplex communication equipment comprising a host device, a plurality of slave devices, a first transmission line and a second transmission line for transmitting data in a direction opposite to that for the first transmission line, wherein the host device and the plurality of slave devices are interconnected in a ring form by the first and second transmission lines, the host device includes a host distributing part and a host path selecting part, and each of the slave devices includes a first slave path selecting part, a slave path distributing part, a second slave path selecting part, a transmitted data control part and a path transmitting part.
The host path distributing part which the host device has transmits the same path to the first and second transmission lines, and the host path selecting part selects a path from the first and second transmission lines.
The first slave path selecting part which each slave device has selects paths which are transmitted through the first and second transmission lines from the host device. The slave path distributing part distributes a path from the first transmission line to the second transmission line and the slave path selecting part. The second slave path selecting part selects paths which are transmitted through the first and second transmission lines from the other slave devices. The transmitted data control part selects data to be transmitted to the host device from received data in the paths selected by the second slave path selecting part and transmitted data of its own device. The path transmitting part transmits the data from the transmitted data control part through paths to the first and second transmission lines.
Data to be transmitted is transmitted from the host device through the path
1
to the two-way transmission lines. In each slave device, the path
1
is transmitted to the adjacent slave device by the path distributing part and output to the slave path selecting part. Paths from both transmission lines are selected by the slave path selecting part and the transmitted data from the host device is output.
A signal transmitted from each slave device is compared with data transmitted from the other slave devices in the transmitted data control part of its own. If transmission is permitted, the signal is output from the transmitted data control part and sent from the path transmitting part to the two-way transmission lines through the path
2
. The host device selects the path
2
for the two-way transmission lines by the slave path selecting part and receives the data.
The host path selecting part of the host device and the slave path selecting part of the slave device operate so as to select a normal transmission line when one transmission line fails.
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patent: 5150356 (1992-09-01), Tsutsui
patent: 5166675 (1992-11-01), Amemiya et al.
patent: 5191579 (1993-03-01), Matsushita et al.
patent: 5278824 (1994-01-01), Kremer
patent: 5282200 (1994-01-01), Dempsey et al.
patent: 5581710 (1996-12-01), Noel, Jr. et al.
patent: 5657446 (1997-08-01), Pinard et al.
patent: 5745476 (1998-04-01), Chaudhuri
patent: 5793754 (1998-08-01), Houldsworth et al.
patent: 5799001 (1998-08-01), Lee et al.
patent: 5815490 (1998-09-01), Lu
patent: 5901137 (1999-05-01), Nakabayashi
patent: 5982747 (1999-11-01), Ramfelt et al.
NEC Corporation
Nguyen Brian
Patel Ajit
Sughrue Mion Zinn Macpeak & Seas, PLLC
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