In the prior art, the signals between telecommunication devices are switched by means of a crossbar switch, which connects the signal coming to it to the right address. A crossbar switch comprises a set of connectors to which a first telecommunication device can be connected, and another set of connectors to which a second telecommunication device can be connected. The prior art connectors are so-called knife connectors. A stripped wire is inserted into the cavity-shaped input hole of the connector, whereby a knife-like device at the end of the cavity splits the wire, thereby providing a better contact between the connector and the wire. The crossbar switch unit also comprises devices, which enable the switching to be performed. Generally, these devices are crossbar switches, electromechanical switches, in which the switching operations are carried out by connecting the electric crossbars with each other. Often the crossbars also include knife connectors to make switching easier and faster.

The crossbar switch described above entails the problem that the connectors must be brought to the knife connectors one by one. This requires high accuracy in order to perform the coupling correctly. Furthermore, because fastening the wires to the connectors requires high accuracy, the fastening is also very slow. This problem is particularly prominent in applications where there are a very large number of wires, such as telephone exchanges.

The crossbar switches available now also have the problem that their manufacturing process is very expensive. Especially the crossbars are expensive. This is due to the fact that there are only a few manufacturers of crossbars, which allows them to set the prices freely.

The prior art crossbar switches can also be provided with protection against overvoltage surges occurring in the mains. An overvoltage surge may, for instance, arise if a stroke of lightning hits the telephone network. This would carry the risk

that the overvoltage surge that arose as a result of lightning reaches the crossbar switch or even the telecommunication device and breaks it. In crossbar switches available today, overvoltage protection is generally provided by a gas-discharge tube, one end of which is connected to the ground and the other end to the subscriber's cable. When the overvoltage reaches the gas-discharge tube, the gas in the tube is ionized, whereby the overvoltage is conducted to the ground and is thus prevented from getting directly to the subscriber's device. A protection method like this is a very expensive solution.

The objective of this invention is to eliminate the above-mentioned drawbacks, which are sometimes associated with the crossbar switches, and to provide a new, improved low-cost solution for signal switching. The invention offers the solution, whereby crossbar-like switching is realized by means of a switching panel, in which the switching mechanism is entirely different from the present solutions. The cables of the telecommunication devices are coupled to the panel by means of connectors.

In the switching panel, the switching is carried out in accordance with the address information of signals running in the signal conductors by using, for instance, jumper wires.

The device according to the invention is characterized in what is set forth in the independent claim 1. The method according to the invention is characterized in what is set forth in the independent claim 8. Other preferred embodiments of the invention are set forth in the dependent claims.

In the following, the invention will be described in more detail with reference to the accompanying drawings, of which Figure 1 shows the location of a switching panel in a telecommunication network, as featured in the invention.

Figure 2 shows a switching panel, as featured in the invention, Figure 3 shows the arrangement principle for performing the switching, as featured in an embodiment of the invention, and Figure 4 shows an example of overvoltage protection, as featured in an embodiment of the invention.

In the figures, the same reference numbers and markings are used for corresponding parts.

Figure 1 shows the location of a switching panel 11 in the telecommunication network, as featured in the invention. In this embodiment, at least one telecommunication device 12 can be connected to the switching panel 11, with the telecommunication device 12 preferably being located on the side of the host network 14. The telecommunication device 12 is connected to the switching panel 11 by cabling. The cables between the telecommunication device 12 and the switching panel 11 are generally called jumper cables. In this embodiment, subscriber devices 13 are connected on the side of the subscriber network 15 of the switching panel 11. In Figure 1, the subscriber devices are illustrated by symbols, which resemble stationary telephone devices, but these subscriber devices 13 can also be any other subscriber devices 13. The cables on the side of the subscriber devices 13 are generally called subscriber cables. As a generalization, it can be said that the switching panel 11 functions as a switching unit between the telecommunication devices 12 of the host network 14 and the subscriber devices 13 of the subscriber network 15. It will be clear to a person skilled in the art that one or more telecommunication devices 12 of the host network 14 and one or more subscriber devices 13 of the subscriber network 15 can be coupled to the switching panel.

Figure 2 shows a switching panel 11 according to the invention. In this embodiment, the switching panel 11 is divided into three blocks. The first block is an input block 21, to which the telecommunication devices 12 of the host network 14 can be coupled. In this switching panel 11, the connections in the direction of the telecommunication device 12 of the host network 14 are realized by using one of the connectors 21 a-f, preferably a standard connector. Using a connector provides the advantage that the conductors coming from the telecommunication device 12 of the host network 14 need not be connected one by one. Instead, the telecommunication device 12 can be easily and quickly coupled to the switching panel 11 using the counterpart for the connector 21 a-f of the switching panel 11 in the jumper cable. A very commonly used type of connector suitable for the jumper cable between the telecommunication device 12 and the switching panel 11 is the euroconnector. The connector used can be of any other type, but preferably one which complies with the generally accepted connector standards.

One or more telecommunication devices 12 of the host network 14 can be connected to the switching panel 11 shown in Figure 2. There should be a sufficient number of connectors 21 a-f in the input block 21 of the switching panel 11 for the telecommunication devices 12. It will be clear to a person skilled in the art that the

number of connectors need not be the same as the number of connectors 21 a-f in the solution shown in Figure 2, but the number of connectors 21 a-f is dependent on the number of conductors in each application and the connector type being used.

The connectors 21 a-f in the input block 21 need not be similar, but a suitable connector for each situation can be selected freely according to requirements.

The telecommunication devices or subscriber devices 13, to be connected to the output block 23 of the subscriber network 15, can also be connected by using the connectors 23 a-e. The connectors 23 a-e are preferably also of some known standard type, but other connectors can also be applied in this embodiment. The connectors 23 a-e need not be similar, either, because the type of the connectors 23 a-e can vary depending on the subscriber device 13 to be connected and the cable used. The number of the connectors 23 a-e of the output block 23 is not prescribed, either.

Signals from the pins 31 of the connectors 21 a-f ; 23 a-e of the input block 21 and output block 23 are brought to the pins 32 of the switching block 22 using a known technique. Figure 3 shows an embodiment of the invention, in which the switching panel 11 is implemented as a circuit board solution. In this embodiment, the pins 31 of the connectors on the circuit board are brought to the switching block 22 using the copper coating of the circuit board, thus enabling the formation of signal conductors 33 from the input block 21 and output block 23 to the switching block 22. The signals of the connectors 21 a-f ; 23 a-e of the input blocks 21 and output blocks 23 can also be brought to the switching block 22 by using some other known technique, such as wiring.

The purpose of the switching block 22 is to combine the signal brought from the telecommunication device 12 of the host network 14, via the connectors 21 a-f, to the right pin 31 of the connectors 23 a-e of the output block 23 of the subscriber device 13. In the switching block 22, the switching can be realized so that, for instance, the signal conductors 33 of the host network 14 and the signal conductors 33 of the subscriber network 15 form a switching matrix. Because the devices coupled to the switching panel 11 are connected in a predetermined manner to the right connectors 21 a-f ; 23 a-e, in the switching matrix it is possible to switch the signal coming to a certain signal wire 33 on either the host network side 14 or the subscriber network side 15 to a certain output signal wire 33. This is achieved by entering the coordinates of the intersection point of the signal wires 33 and by connecting the signal wires 33 mentioned in the switching matrix by means of some switching devices. These switching devices can be, for instance, the jumper wires

32. When jumper wires are used, the signal wires 33, corresponding to the coordinates of the switching matrix, are connected by a jumper wire 32. The jumper wires 32 can be controlled manually or, for instance, by remote-controlled robots.

The switching can also be implemented by using known electromechanical switches with suitable settings as switching devices between the input and output side of the switching block 22, whereby the desired switching can be carried out by controlling the electromechanical switches. It will be clear to a person skilled in the art that it is possible to form several connections simultaneously between the input block 21 and the output block 23. The switching devices can also be various systems of switches and couplings, which can be applied to this invention.

In one embodiment of the invention, the switching can be implemented digitally.

The digital switching is preferably implemented by using a microprocessor. The microprocessor could, for instance, read an address from a signal coming from a telecommunication device 12 on the side of the host network 14, which denotes the intended connection for the signal, whereupon the microprocessor guides the signal to the pin 32 of the output block 23 in the switching block 22, which corresponds to that address. It will be clear to a person skilled in the art that the signal can also be switched digitally in many ways other than the one used in this example.

In one useful embodiment of the invention the switching panel 11 is provided with protection against overvoltage surges occurring in telecommunication networks. The preferred place for this protection is between the input and output of the switching panel 11. The protection can also be placed elsewhere, such as between the output of the switching panel 11 and the subscriber network 15. Figure 4 shows an example of protection against overvoltage surges between the input block 21 and the output block 23 of the switching panel 11. One way of implementing the protection is to place a protecting wire 41 connected to the ground by some prior art method between the input block 21 and output block 23. The preferred implementation of protecting wire 41 would allow it to pass the normal signals of the switching panel 11. In the event of an overvoltage surge, however, the mode of the protecting wire 41 would become very conductive, whereby the overvoltage surge would be led directly to the ground. The type of overvoltage protection described above can be conveniently arranged by the right selection of materials. However, protection against overvoltage surges in a switching panel 11 can also be arranged in many ways other than the one described in the example above. As illustrated in one embodiment of the switching panel 11 shown in Figure 4, the connectors 2 la ; 23 a

of the subscriber cables can be placed on any surface of the switching panel 11, and their number can be selected freely according to requirements.

The switching panel 11 proves advantageous when applied in a base station of a cellular radio system, in which the connection to the data transfer system is implemented by a switching system. Another application for the switching panel 11 could be found in telephone exchanges and transfer devices, to which subscribers are connected and in which the frequency and volume of connections is very large.

It will be clear to a person skilled in the art that a switching panel 11, as featured in the invention, can also be applied in all other systems and devices in which the frequency and volume of connections is large. Still another application for the switching panel 11 can be found in the process industries, such as the paper industry, where large installations, such as paper machines, need a lot of control and monitoring, and in which the signal switching can be implemented by the use of a switching panel 11 as described above.

It will also be clear to a person skilled in the art that the individual components of the switching panel 11, as described above, are not limited in any way : other components, which are suitable for implementing the switching as featured in the invention, and which are possible within the scope of the inventive idea defined in the attached claims, can also be used. The terms input block 21 and output block 23 given above are only intended for making a distinction between the blocks. The names do not limit the directions of the signals coming to the switching panel 11, or other matters related to the operation of the switching panel 11. Signals can come to the switching panel 11 from both the direction of the host network 14 and the direction of the subscriber network 15, and the switching panel 11 connects the signals in both directions as described above. The operational components of the switching panel 11 can also be divided into blocks in ways other than those described in the example above.