JPH0758964B2 - Multi-drop LAN forming device - Google Patents

Description

DETAILED DESCRIPTION [Outline] A device for forming a multi-drop LAN between a plurality of terminals via a network in a private branch exchange,
It consists of multiple LAN units that are connected vertically to each other, and each LAN unit has a common forward and return path that can be vertically connected between adjacent LAN units, and the data that is connected to these paths. It consists of a forward path and a return path, a folded part provided at one end of the LAN unit, and a connection / disconnection part provided at the other end of the LAN unit for connecting / disconnecting with an adjacent LAN unit. Can form a drop LAN.

[Industrial application field]

The present invention relates to a multi-drop LAN (Local Area Network) forming device.

For example, in an intelligent building, a so-called distributed exchange system is constructed, and various information is exchanged within each floor of the building or between an external network and each floor. A loop network is formed in the building to exchange this information, and a group of terminals in each floor and the loop network are connected via each node. Under each node, each node forms a multi-drop LAN for each floor or tenant, and it is possible to communicate between many terminals of each multi-drop LAN. Here, terminals are digital telephones, FA
It is a concept that includes OA equipment such as X devices and personal computer terminals.

Generally, when all terminals on one floor need to communicate data with each other, it is inconvenient for the system if only 1: 1 data communication between two terminals is possible. It is realistic to have a multi-drop configuration so that n: n data communication can be performed between them.

[Conventional technology]

In order to form the above-mentioned multi-drop LAN, the applicant pays attention to a private branch exchange (PBX) that is always installed in a building,
It was considered to realize high-speed data communication in a LAN format between a plurality of terminals via the network in the PBX.

FIG. 5 is a diagram showing an example of a conventional multi-drop LAN forming apparatus. In the figure, 11 is a private branch exchange (also called PBX), and its core is a network (NW) 12. Then, a multi-drop LAN forming device 13 is attached to this network 12. The network 12 also accommodates a plurality of terminals 14. Multi-drop LA among these terminals 14
Two or more terminals 14 which intend to mutually perform high-speed data communication under N are mutually connected by the multi-drop LAN forming device 13.

The multi-drop LAN forming device 13 forms an n: n multi-drop line for constructing a bus LAN.
Then, a case where a data highway device is used is shown as an implementation example. However, the configuration in this figure is a multi-drop configuration drawn in an easy-to-understand manner. Actually, the 1: n multi-drop line function is converted to the n: n multi-drop line function by time division multiplexing. Expand and use. In the figure, 18 is a parent connector (CN), and the rest are all child connectors (CN) 19. 1-1, 1-2, 2-2 in each connector
The numbers such as are a matrix display of each position. For example, 1-1 corresponds to the first row of the first column, and 2-2 corresponds to the second row of the second column. Here, the directionality of data is defined for the connection between the connectors. Since both are the same, looking at d, e and f of connector connections, for example,
Between d and e (illustrated to be connected smoothly), data can be transferred in either direction from d to e or from e to d. This is the same between ef (drawn straight). However, d-
No data is transmitted between f (drawn at an acute angle) in either direction from d to f or f to d. The operation of the multi-drop line using such a connector will be described below in an easy-to-understand manner.

FIG. 6 is a diagram schematically showing the function of the apparatus shown in FIG.

In this figure, the 1: n multi-drop line system is
Four columns up to four are shown. As described above (explained by using d, e, and f in FIG. 5), each system can communicate between the parent and the child, but cannot communicate between the child and the child. In this case, n: n communication between the plurality of terminals 14 cannot be performed, so four systems are formed by time division multiplexing (enclosed by dotted lines) so that communication can be performed between the children. Lines g, h and i show with three examples that a communication path can be formed between children.

[Problems to be Solved by the Invention]

The above-described conventional multi-drop LAN device 13 uses, for example, a data highway device, and is excellent in data quality. However, there are problems with the expandability and cost of the LAN. In other words, when the number of terminals that want to use the multi-drop LAN increases, it lacks the flexibility to support this. In addition, the device itself is expensive, and since the number of devices used is large, the PBX becomes expensive.

Therefore, an object of the present invention is to provide a multi-drop LAN forming device which is highly flexible and can be realized at low cost in view of the above problems.

[Means for Solving the Problems]

FIG. 1 is a diagram showing the principle configuration of the present invention. In addition to the multi-drop LAN forming device 13 according to the present invention, a network (NW) 12 and a terminal 14 are also drawn.

The multi-drop LAN forming device 13 of the present invention is formed by vertically connecting a plurality of LAN units 20 to each other.

Each LAN unit 20 includes a common outward path 21 for the above-mentioned vertical connection and a common backward path 22 paired with the common outward path 21.
And a buffer amplifier 25 inserted in the common return path 22,
Data return path connected to the output side of the buffer amplifier 25
24, and a data outbound path 23 that connects with one of two or more terminals 14 via the network 12 together with the data inbound path 24.
And a data insertion unit 26 connecting the data forward path 23 and the common forward path 21, and a LAN on the input side of the buffer amplifier 25.
The loopback path 27 provided at one end of the unit 20, the loopback switch 28 that connects or disconnects the loopback path 27 with the common forward path 21 and the common return path 22, and the LAN unit 20 on the output side of the buffer amplifier 25. Coupling / separating switch that is provided at the end and connects or disconnects the common forward path 21 and common return path 22 with the adjacent LAN unit 20
It consists of 29 and.

[Work]

The data transmitted to the data outbound path 23 is transferred on the common outbound path 21 of each LAN unit 20, returned by the return path 27 of another LAN unit 20, and transferred on the common return path 22. The connection of the folding path 27 to the paths 21 and 22 is performed by driving the folding switch 28. The LAN unit in which the folding switch 28 is driven is the LAN unit 2 located at the end of the group of terminals forming one LAN.
It is 0.

Thus, the data returned on the common return path 22 is
The data is transferred to each terminal 14 through the data return path 24 of the LAN unit 20.

Grouping of terminals forming a LAN is combined /
This is done by the separation switch 29, and if it is turned off, it is separated from the adjacent LAN unit 20.

The data transmitted from the transmitting terminal is put on the common outward path 21 from the data outward path 23 via the data insertion unit 26. The data placed on the path 21 travels on the common return path 22 by the return path 27. At this time, a buffer amplifier 25 is provided to prevent the level of the data signal from being attenuated.

FIG. 2 is a diagram showing an embodiment of the present invention, in which three stages of the vertically connected LAN units 20 are taken out and shown.
An example is shown in which one group of multi-drop LANs is constructed between the three terminals 14 corresponding to each of these three-stage LAN units 20. To make this one group, the contacts 29-1 and 29-2 forming the coupling / separation switch (29) of the leftmost LAN unit 20 are turned off. That is, the left LAN
Separate from the unit. The contacts 29-1 and 29-2 may be relay contacts or semiconductor contacts made of transistors. In addition, the return switch (28) of the LAN unit 20 at the right end
The contacts 28-1 and 28-2 forming the connection are connected to the folded path 27 side. The contacts 28-1 and 28-2 may be the same as the contacts 29-1 and 29-2.

For example, the transmission data from the terminal corresponding to the central LAN unit 20 enters the data insertion unit 26 through the data outward path 23. An OR gate is used in this embodiment. If possible, wired OR is acceptable. From the data insertion unit 26 through the common forward path 21, the return path 27, and the common return path 22,
It is output from the data return path 24 and received by each corresponding terminal.

As you can see, the contacts 28-1, 28-2 that make up the folding switch,
It is possible to easily group LANs by turning on / off the contacts 29-1 and 29-2 that form a coupling / separation switch, and it is also possible to easily deal with the addition of terminals. Also, as shown, no expensive device is used.

In the LAN unit 20 at the left end in FIG. 2, the upper terminal of the contact 29-1 in the coupling / separation switch is clamped to a predetermined potential V, and the OR gate 26 is logic "L" (low).
Is given.

Further, each LAN unit 20 can be integrally formed on one printed circuit board. Alternatively, a plurality of daughter boards equipped with the LAN units 20 can be formed upright on a single motherboard. At this time, the mother board and the daughter board can be attached and detached by a connector.

FIG. 3 is a diagram showing a configuration example of a multi-drop LAN between floors. As shown, LAN unit groups corresponding to the terminal groups in floor F2 on the upper floor and floor F1 on the lower floor
A large-scale multi-drop LAN can be easily constructed with the LAN unit group corresponding to the terminal group inside. This is 3
The same is true when straddling more than one floor. Simply connect any one LAN unit 20 on each floor with a floor-to-floor connection line 31.

FIG. 4 is a diagram showing an application example of the present invention, showing an example in which a private branch exchange of each floor is formed in the floor station FS, and the floor stations FS are connected by an inter-floor connection line 31. The figure shows the case where the optical loop network is used. The CC in each floor station is a control processor and performs switching control for the network 12 and ON / OFF control of each switch described above provided in the multi-drop LAN forming device 13. This on / off control is performed according to a request command which terminal wants to form a multi-drop LAN with which terminal. In the figure
MDF is a terminal board.

〔The invention's effect〕

As described above, according to the present invention,
In addition, a multi-drop LAN can be formed at low cost.

[Brief description of drawings]

FIG. 1 is a diagram showing a principle configuration of the present invention, FIG. 2 is a diagram showing an embodiment of the present invention, FIG. 3 is a diagram showing a configuration example of a multi-drop LAN between floors, and FIG. FIG. 5 is a diagram showing an application example of the invention, FIG. 5 is a diagram showing an example of a conventional multi-drop LAN forming device, and FIG. 6 is a diagram schematically showing the function of the device of FIG. In the figure, 12 ... network, 13 ... multi-drop LAN forming device, 14 ... terminal, 20 ... LAN unit, 21 ... common forward path, 22 ... common return path, 23 ... data forward path, 24 ...... Data return path, 25 …… Buffer amplifier, 26 …… Data insertion section, 27 …… Folding path, 28 …… Folding switch, 29 …… Coupling / separating switch.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H04Q 11/04 8732-5K H04L 11/00 310 A

Claims (1)

[Claims] 1. A private branch exchange which houses a network (12) and accommodates a plurality of terminals (14), and between any two or more of the terminals (14) via the network (12). , A multi-drop LAN forming device (13) for forming a multi-drop LAN (Local Area Network), which is formed by vertically connecting a plurality of LAN units (20) having the same configuration to each other. (20) is inserted in the common outward path (21) for the cascading connection, the common return path (22) paired with the common outward path (21), and the common return path (22). Buffer amplifier (25) and the buffer amplifier (2
5) A data return path (24) connected to the output side, and a data forward path connected to one of the two or more terminals (14) via the network (12) together with the data return path (24) (23), a data insertion section (26) connecting the data outward path (23) and the common outward path (21), and one end of the LAN unit (20) at the input side of the buffer amplifier (25). A return path (27) provided, a return switch (28) for connecting or disconnecting the return path (27) to or from the common outward path (21) and the common return path (22), and the buffer up ( 25) is provided at the other end of the LAN unit (20) on the output side of the common forward path (21) and the common return path (22).
It is configured with a coupling / separation switch (29) for connecting or disconnecting the LAN unit (20) and dividing the LAN into one or more groups, and the common forward path (21) at the end of each group. ) And the common return pass (2
A multi-drop LAN forming device, characterized in that it is connected to 2) by the folded path (27).