JPH0645964A - Signal distributor - Google Patents

Abstract

PURPOSE:To prevent the performance of a signal distributor from being lowered and to extend a transmission distance by suppressing the distribution loss of the signal distributor to the minimum even when the number of ports to be used is changed in the signal distributor for an information wiring system to be used for information communication. CONSTITUTION:The passive type signal distributor for the information wiring system is provided with plural distribution circuits B1, B2 and switching circuits SW1, SW2 for selecting respective circuits B1, B2 so as to obtain the necessary number of pieces of distribution. The circuits B1, B2 are divided into plural sections, which are switched by the switches SW1, SW2, so that the optimum circuits B1, B2 can be selected in accordance with the number of pieces of distribution required by a user, a distribution loss can be suppressed to the minimum and a transmission distance can always be maximized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal distributor used for distributing signals to a plurality of input / output ports in an information wiring system.

[0002]

2. Description of the Related Art FIG. 2 is a schematic configuration diagram of a conventional information wiring system that communicates by a balanced signal. The controller 1 and the terminal 5 include a balanced cable 4 such as a twisted pair cable, a balanced-unbalanced converter 3 for mutually converting a balanced mode signal and an unbalanced mode signal, and the controller 1 or the terminal 5. And a balanced-to-unbalanced converter 3 are connected by a coaxial cable 2. In the configuration of FIG. 2, one terminal device 5 is connected to one controller 1, but as shown in the configuration of FIG. 3, a plurality of terminal devices 5 may be multipoint-connected. When topology-converting a LAN configured by such multipoint connection to star wiring, as shown in FIG. 4, the signal distributor 6 is inserted at the connection point between the balanced-unbalanced converter 3 and the balanced cable 4. There is a need to. In the configuration of FIG. 4, the signal transmitted from the controller 1 is input from the first port of the signal distributor 6 via the coaxial cable 2 and the balanced-unbalanced converter 3, and is incorporated in the signal distributor 6. The signal is distributed by the signal distribution circuit, is output from the second to fifth ports of the signal distributor 6 to the balanced cable 4, and is received by the terminal device 5 via the balanced-unbalanced converter 3 and the coaxial cable 2. Similarly, the signal transmitted from the terminal 5 is also transmitted in the opposite direction through the same route as described above and received by the controller 1.

5 and 6 show a conventional passive type signal distribution circuit. FIG. 5 shows a four-distribution circuit, in which the signal from the port P1 on the controller side is transferred to the four ports P on the terminal side.
2 to P5. Further, FIG. 6 shows an 8-distribution circuit, which distributes the signal of the port P1 on the controller side to the eight ports P2 to P9 on the terminal side. When the two are compared, the distribution number of the 8-distribution circuit is larger than that of the 4-distribution circuit, so that the distribution loss becomes large.

[0004]

In the above-described conventional example, since the passive type signal distribution circuit is used, there is a problem that the signal distribution circuit having different specifications must be used according to the distribution number. Further, when the number of ports used is smaller than the number of distributions of the signal distribution circuit, the distribution loss by the signal distribution circuit becomes unnecessarily large and the transmission distance is limited.

The present invention has been made in view of the above points, and it is an object of the present invention to minimize distribution loss due to a signal distributor even when the number of ports used changes. This prevents the performance of the signal distributor from deteriorating and extends the transmission distance.

[0006]

According to the present invention, in order to solve the above-mentioned problems, as shown in FIG. 1, in a passive type signal distributor of an information wiring system, a plurality of distribution circuits B1 are provided. , B2 and a switching circuit SW that selects the distribution circuits B1 and B2 so that the required number of distributions can be obtained.
1 and SW2 are provided.

[0007]

According to the present invention, by dividing the distribution circuits B1 and B2 into a plurality of parts and switching them by the switching circuits SW1 and SW2, the optimum distribution circuits B1 and B2 are selected according to the distribution number desired by the user. As a result, the distribution loss can be minimized, and the transmission distance can always be maximized.

[0008]

FIG. 1 is an internal circuit diagram of an embodiment of the present invention. This signal distributor has an input / output port P1 connected to the controller side and an input / output port P1 connected to the terminal side.
2 to P9. This signal distributor is capable of distributing signals up to 8 distributions, and includes a 4 distribution circuit B1, a 2 distribution circuit B2, and first and second switching circuits SW1 and S1.
W2 and. The input / output port P1 on the controller side is distributed to four input / output ports by the four-distribution circuit B1. These four input / output ports can be switched to either contact a or contact b by the first switching circuit SW1. Each contact a of the first switching circuit SW1 is connected to the second switching circuit SW1.
2 is connected to each contact a. The second switching circuit SW2 is capable of switching the input / output ports P2 to P5 to the contact a or the contact b. The first and second switching circuits SW1 and SW2 are interlocked and switched, and either the state connected to the illustrated contact a or the state connected to the contact b opposite to the illustrated state is connected. To be selected. When switched to the contact b, the signal of each contact b of the first switching circuit SW1 is divided into two distribution circuits B2.
Are distributed to the input / output ports P2 to P5 via the contacts b of the second switching circuit SW2 and also to the input / output ports P6 to P9.

If the number of distributions desired by the user is 4 or less, the first and second switching circuits SW are
1, SW2 is switched to the state of being connected to the illustrated contact a. In this case, the input / output port P1 on the controller side
Signals of four input / output ports P by the four-distribution circuit B1.
2, P3, P4, P5. When the number of distributions desired by the user is five or more, the first and second switching circuits SW1 and SW2 are switched to the state in which they are connected to the contact b opposite to the state shown in the drawing. in this case,
The signal of the input / output port P1 on the controller side is divided into eight input / output ports P by the four distribution circuit B1 and the two distribution circuit B2.
2 to P9.

[0010]

In the signal distributor of the present invention, the distribution circuit is switched according to the number of distributions desired by the user, so that the distribution loss by the distribution circuit is minimized and the transmission distance in the information wiring system is always maintained. The effect is that it can be maximized.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a conventional one-to-one connection information communication system.

FIG. 3 is a schematic configuration diagram of a conventional multipoint connection information communication system.

FIG. 4 is a schematic configuration diagram of a conventional star wiring information communication system.

FIG. 5 is a block diagram showing an example of a conventional distribution circuit.

FIG. 6 is a block diagram showing another example of a conventional distribution circuit.

[Explanation of symbols]

 P1, P2, ..., P9 I / O ports B1 4 distribution circuit B2 2 distribution circuit SW1 first switching circuit SW2 second switching circuit

Claims (1)

[Claims] 1. A signal distribution device of a passive type for an information wiring system, comprising: a plurality of distribution circuits; and a switching circuit for selecting the distribution circuits so as to obtain a required number of distributions. vessel.