GB2457697A

GB2457697A - Switching and testing arrangement for telephone networks, using power provided over phone line

Info

Publication number: GB2457697A
Application number: GB0803191A
Authority: GB
Inventors: David Mather
Original assignee: Tyco Electronics Raychem BVBA
Current assignee: Commscope Connectivity Belgium BVBA
Priority date: 2008-02-21
Filing date: 2008-02-21
Publication date: 2009-08-26
Anticipated expiration: 2028-02-21
Also published as: GB2457697B; GB0803191D0

Abstract

Electrical switching apparatus is described for connection to a wiring terminal block for a distribution frame, the wiring terminal block being connected to a plurality of telephone lines, cartridges inserted into the terminal block and a switching means in the cartridge for line-by-line switching, a power supply for powering the operation of the switching means being provided via one of the telephone lines connected to the wiring terminal block. The telephone line used for the power supply is a line of a telephone cable connected to the wiring terminal, whereby the other lines of the cable are for providing a telephone service and the line used for the power supply is not used for a telephone service. The power supply may be a remote power supply that is selectably connected to the telephone line used to provide the power supply by a test access matrix system. The test access matrix system is adapted to connect lines used for a telephone service selectably to a test head.

Description

I

SWITCHING AND TESTING ARRANGEMENT FOR TELEPHONE

NETWORKS

This invention relates to electrical switching and testing apparatus for use in telecommunication systems and networks, methods of operating and method of manufacture of the same. The apparatus and methods are particularly adapted to enable telecommunications service providers to replace existing equipment with new equipment, with minimal or no loss of service. The invention further relates to a method of connecting new equipment into a telecommunications system. The present invention relates to new or additional services, e.g. xDSL services such as ADSL, in a telecommunication system, e.g. a telephone system especially to methods of interconnection and to interconnection points for connecting telecommunication ::::* services. The present invention particularly relates to the provision of disconnection and connection points in a telecommunication system.

:.: is

* Technical Background

:*::* Telephone networks comprise cables with metallic pairs. A pair may be connected to an * individual customer line. At various places in the network, distribution boards may be placed into which terminal blocks are placed, e.g. at main, intermediate, horizontal or vertical distribution frames. These terminal blocks can be adapted to provide through-connections for around 100 pairs. It is customary to provide test access to the telephone lines and a conventional system is shown in Fig. I for this purpose.

The terminal blocks provide interconnection points for the telephone lines and tdecommunications equipment such as test equipment. A test access matrix (TAM) system is shown in Fig. 2. Terminal blocks 2 are located in a distribution frame such as a main distribution frame. Lines 4, e.g. 1 to 100 from one block go to a subrack 6 of a test access matrix system 9. The TAM system 9 has a means for selectively and remotely connecting a line 4 to a test head 10. To do this a switching device 11 is provided such as a cross-bar switch which is used to select a relevant subrack 6 and a line 4 within that subrack for testing.

Internet access from home can be provided via a plain old telephone service (POTS), where a telephone line comprising a pair of copper wires provides a two-way communication path between a modem and a central office (CO). The latter connects the modem to a specified on-line service provider through a public switched telephone network (PSTN). Telephone companies are introducing new services, including an asymmetric digital subscriber line (ADSL) service, which permits fast on-line access.

For example, the ADSL service supports uplink traffic having a lower bit rate than the downlink traffic. For economic reasons, the ADSL traffic traverses the same copper wire pair traditionally used as the telephone line in the POTS. A general reference to xDSL telecommunication systems is: "ADSL & DSL Technologies, 2"' Ed., W. J. Goraiski, Osboume/McGraw Hill, 2002.

Nowadays, telecommunication central offices are being upgraded on the one hand to provide extra DSL services and secondly to save space by replacing old electronic devices, e.g. a legacy switch, by new switches/electronic devices (e.g. MSAN). From service level point of view it is often unacceptable to bring the new switch or equivalent electronic device (e.g. MSAN) in service from day one and directly physically decouple the old switch or electronic device. Cutting copper wires to obtain such replacement is often not accepted as an option, because cabling cannot always be cut near the relevant connector block due to space restrictions and accessibility. Then cutting the copper wires creates a stub effect. Hence there is a need for a disconnection :*::* point.

* Historically, the replacement of legacy equipment by newer equipment has involved the manual rewiring. For example, the legacy and the new equipment could be connected in parallel before the legacy equipment was disconnected. This is a labour intensive, time consuming and expensive process requiring a large number of skilled technicians. A further drawback of such known methods is that, in the event that the new equipment becomes defective connecting up to the legacy equipment again requires further manual intervention on site.

GB 2425223 describes an electrical switching apparatus for connection to a five point overvoltage protector socket on a standard telecommunications exchange wiring block, in which the five points comprise a first pair of connection points for connecting a customer circuit, a second pair of connection points for connecting telecommunications exchange equipment, and an earth connector adapted to receive an overvoltage protector module, and in which the first pair of connection points is normally connected to the second pair via said overvoltage protector module, which electrical switching apparatus comprises: a third pair of electrical connection points for connecting further telecommunications equipment; and switching means adapted to be varied between a first state in which the first pair of connection points is electrically connected to the second pair of connection points, and a second state in which the first pair of connection points is connected to the third pair of connection points. The switching means may comprise a relay. The switching means is incorporated into a modified overvoltage protector module. There is one switching means per customer line and all the switches are arranged in rows and columns of an XY array or grid. In order to operate a relay, voltages are applied to the relevant specific row and column of the grid. This apparatus requires separate wiring to operate the relays.

Summary of the Invention

An object of the present invention is to provide an alternative electrical switching apparatus and switching method for a telecommunications network.

According to an aspect of the present invention, there is provided electrical switching apparatus for connection to a wiring terminal block for a distribution frame, the wiring terminal block being connected to a plurality of telephone lines, cartridges inserted into the terminal block and a switching means in the cartridge for line-by-line switching, a power supply for powering the operation of the switching means being provided via one of the telephone lines connected to the wiring terminal block. The :*. telephone line used for the power supply is a line of a telephone cable connected to the wiring terminal, whereby the other lines of the cable are for providing a telephone service and the line used for the power supply is not used for a telephone service. The apparatus may also comprise a first pair of connection points for connecting a customer circuit, a second pair of connection points for connecting teleconununications exchange equipment and a third pair of electrical connection points is provided for connecting further telecommunications equipment, the switching means having a first switching state in which the first pair of connection points is electrically connected to the second pair of connection points, and a second switching state in which the first pair of connection points is connected to the third pair of connection points, and a power supply via one of the lines connected to the wiring terminal block. The power supply may be a remote power supply that is selectably connected to the telephone line used to provide the power supply by a test access matrix system. The test access matrix system is adapted to connect lines used for a telephone service selectably to a test head.

According to another aspect of the present invention, there is provided electrical switching apparatus for connection to a wiring terminal block for a distribution frame, comprising a first pair of connection points for connecting a customer circuit, a second pair of connection points for connecting telecommunications exchange equipment, and an earth connector optionally adapted to receive an overvoltage protection module. The first pair of connection points is normally connected to the second pair, e.g. via the overvoltage protection module. A third pair of electrical connection points is provided for connecting further telecommunications equipment. Switching means are provided for line-by-line switching, the switching means having a first switching state in which the first pair of connection points is electrically connected to the second pair of connection points, and a second switching state in which the first pair of connection points is connected to the third pair of connection points. The switching means may be a relay. A third pair of connection points is carried in a cartridge adapted to be plugged into the exchange wiring block. The switching means is powered over a line pair of telephone cables connected to one of the cartridges inserted in the terminal block. The : . line pair for powering the switching means is selectable in a test access matrix system.

Other line pairs connected to the terminal are used for carrying a telephone service and are selectably connectable to a test head via the test access matrix system.

The apparatus may also include an electronics module that is powered by electrical power supplied through the telephone line. The electronics module can be * ** :*. adapted to selectably route electrical power to the switching means. The electronics module can be detachably connected to the wiring terminal block.

According to a second aspect of the present invention, there is provided a telephone exchange incorporating electrical switching apparatus as described above.

According to a third aspect of the present invention there is provided a method of connecting new equipment to a telecommunications exchange on a line-by-line basis, which method comprises feeding electrical power to a terminal block of a distribution frame via a line of a telephone cable, and controlling switching of a switching means local to the terminal block remotely via a line of the telephone cable. The method includes operating the switching means to change from a first state into a second state, to thereby connect a customer circuit to new telecommunications equipment, and optionally to disconnect a customer circuit from legacy equipment. The method may include disconnecting existing telecommunications equipment from the second pair of connection points.

It is envisaged that the present invention will find use particularly, though not exclusively, for the upgrading of telecommunications exchanges from normal (POTS) telephony equipment to broadband equipment such as an xDSL service. The capability to switch customer premises temporarily back to prior telecommunications equipment should the need arise is also allowed.

Brief Description of the Drawings

In order that the present invention may be more fully understood, preferred embodiments thereof will now be discussed in detail, though only by way of example, with reference to the following drawings in which: Figure 1 shows a schematic representation of an arrangement for providing legacy and new services at a customer premises.

Figure 2 shows a convention test access matrix system.

Figure 3 shows a schematic representation of a terminal block according to an embodiment of the present invention.

Figure 4 shows a schematic representation of a pluggable cartridge in accordance with an embodiment of the present invention.

Figure 5 shows a schematic representation of the disconnectable components of a terminal block arrangement cartridge in accordance with an embodiment of the present * *. invention. I S * * .5

. : Figure 6 shows a test access matrix system with power controller in accordance with an embodiment of the present invention.

Figure 7a-c show a schematic representation of a further embodiment of the present invention.

Figures 8a to d show a schematic representation of capabilities of all the embodiments of the present invention illustrating the switching capability.

Figures 9a to c shows a terminal box including cartridges according to the embodiment of Figure 7.

Detailed description of the illustrative embodiments The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn to scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

It is to be noticed that the term "comprising", used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifing the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression "a device comprising means A and B" should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B. *.*.S The present invention provides a disconnect point for upgrading and/or providing an additional service, e.g. an xDSL service, in a telecommunications network, e.g. a POTS. An advantage of the present invention is that space is saved by replacing old electronic devices, e.g. a legacy switch, by new switches or electronic devices (e.g. MSAN) using a compact system that makes use of cable systems used for other * purposes. From service level point of view it is often unacceptable to bring the new switch or equivalent electronic device (e.g. MSAN) into service from day one and directly physically decouple the old switch or electronic device. Instead, it can be done in phases and additionally the transition between phases can be established so that down time is minimized. For example the present invention allows: Phase I for coupling the new switch/electronic device (e.g. MSAN) to the network (non-functionally) on an line-by-line basis while the relevant service can optionally still be provided by the old electronic device. Phase 2 comprises switching off the old switch (e.g. legacy switch), and bringing the new electronic device into service on a line-by-line basis. It is possible to switch back to the legacy device. This gives the advantage to bring the old switch back in service in case problems occur in the transition period. The third phase is to physically disconnect the old electronic device by means of a mechanical or electrical disconnect at the connector block level which effectively cuts the copper wire interconnection on a line-by-line basis. After this step the old equipment and cabling is removed and space becomes available again. The present invention has the advantage that it allows this last disconnection as close as possible to the connector block to avoid signal interference due to external factors, e.g. to lengths of cut cable (e.g. the stub effect).

An aspect of the present invention is to make electrical switching points, e.g. connection and/or disconnection points, at the line-by-line level with a connector block, e.g. at the customer side or switch side, and integrate a fast, compact and reliable connection system for a new electronic device in one block. Electrical disconnection and/or connection can be realized by controllable or activatable devices, e.g. remotely or locally controllable and activatable devices, such as switching means. The switching means may be latching relays or equivalent. Such devices have at least two states. The activation may be local or remote to the connector block.

Alternative or additional switching services may be provided, e.g. test access * may be included at the connection/disconnection point on a line-by-line basis, e.g. the connection/disconnection point may include a test access module as an alternative to or s.

in addition to the connect/disconnect capability.

In one aspect the present invention provides an integrated line-by-line * connection/disconnection system using pluggable cartridges or modules of terminal blocks, optionally with a test access module, especially a system comprising a simple click-on module established at connector block level. Switching between old and new * " electronic devices can be realized on a line-by-line basis. This allows upgrading of current copper networks in central offices, e.g. for addition of xDSL, such as ADSL services, or for upgrading remote locations.

Figure 3 shows a schematic view of a terminal wiring block 1 of a distribution frame such as a Main Distribution Frame (MDF). This device may be located in a central office, an exchange or remotely. Connector cartridges 25 are locatable in a connection and protection plane 3 of the wiring terminal block of the MDF which couple an input signal applied to the signal plane 5 via a connection and protection plane to the jumper plane 7. The signal plane 5 is the equipment side of the MDF, i.e. is connected to a legacy device such as a legacy switch. The present invention relates to a modified version of the connector cartridge 25 and the terminal wiring block I which allows a variety of possibilities, e.g. the connection of a new service or equipment while maintaining legacy services or maintaining potential access to legacy services or also allowing disconnection of the legacy service once the new service is functional, or disconnection of the new service and return to the legacy service if this is necessary as well as test access -all on a line-by-line basis.

A schematic generic connector cartridge 25 in accordance with embodiments of the present invention is shown in Fig. 4. The functional elements of the connector cartridge 25 are: A block housing or body 16 made of an insulating material such as plastic. Conductive elements, e.g. metal elements 19 are provided which are connectable to the distribution frame, e.g. plug into the connection and protection plane and are used to connect to ground potential. Also connectors 26 (typically 4 per line pair) are provided for connecting the signal plane 4 of the MDF to connections on the jumper plane 5 so that a signal applied to the signal plane 4 is transferred to the jumper plane 5 via the connection and protection plane via a first signal path. Optionally protection units can be provided (not shown) which can be integrated with the connections 26 to provide :*::* protection, e.g. overvoltage protection. The connections 26 co-operate with pins sticking *...

up from the terminal block 1 of the distribution frame to provide connections for the signal paths. The inverse could be the case, e.g. pins in the connector cartridge and connectors in the distribution frame, or any other method of making electrical connections. In addition two relays 8, 8' are provided per line pair for providing the selectable switching on a line-by-line basis of the present invention. The relays 8,8' :*. provide connection points. The relays 8, 8' may be used for any suitable application. For example, these relays 8, 8' can be configured to section a line pair ready for connection of one section or the other to a test head, to allow non-invasive (high impedance) test access to the line pair, to connect or to transfer each line pair, e.g. for test or traffic purposes, etc. Relays, e.g. latching relays, 8, 8' may alternatively or additionally be adapted to connect a line pair to or disconnect a line pair from a legacy device and/or a new equipment on a line-by-line basis. In the following, the present invention will mainly be described with reference to the switching in and out of legacy devices and/or new equipment or services. The signal to be applied to the signal plane is provided from a legacy device such as a legacy switch. Connection unit 13 is a connector for connecting new equipment to the MDF. It provides a second signal path for a signal from the new equipment to the jumper plane 7. There can be parallel first and second signal pathways between the legacy equipment and the jumper plane and between the new equipment and the jumper plane, respectively. Optionally, only one of the pathways is available depending on whether the connector cartridge 25 is in a first state or a second state -this state being determined by the state of the relays 8, 8'. The transition between the first state and the second state is provided by the states of the relays 8, 8' for each line pair.

The cartridge 25 has a first pair of connection points for connecting a customer circuit, a second pair of connection points for connecting telecommunications exchange equipment and a third pair of electrical connection points is provided for connecting further telecommunications equipment, The change from one state to another of the relays 8, 8' can be achieved by remote operation. In a first state, the relays 8, 8' allow at least the second signal path, whereas in the second state at least the first signal path is allowed. In the first state both the first and second signal paths may be allowed in parallel or only the second signal path. In the second state both the first and second signal paths may be allowed in parallel or only the first signal path.

Alternatively, in a first state the relays 8,8' allow at least the first signal path, * ** whereas in the second state at least the second signal path is allowed. In the first state both the first and second signal paths may be allowed in parallel or only the first signal path. In the second state both the first and second signal paths may be allowed in *:. 15 parallel or only the second signal path.

The new equipment may be connected using a fan-out, e.g. with multi-pair connectors which connect to connectors 13 on the pluggable cartridges 25. A connector, e.g. on a fan-out, can be connected to connector 13 and provides the connection to the new equipment. The connector 13 may include additional interconnection devices to select a certain number of cable pairs from the total number of these available in the fan-out connector, e.g. to select 5 out of 25 pairs. The fan-out, for instance, can have 25 pair connectors or 5 pair connectors.

In addition a connector 12 is provided for connection to control electronics thus allowing control of the relays 8, 8' and connection for example to a test access point may be provided. Connector 12 is preferably so adapted that it is connected to a corresponding connector 22 of an electronics module 20 when the cartridge 25 is inserted into the terminal block 1, i.e. connector 12 plugs into connector 22 for each cartridge 25 (see Fig. 3).

The electronics module 20 is located on and optionally can be disconnectable from, or optionally partly disconnectable from its terminal block 1. The electronic module 20 can be adapted to: a) Provide a local network interface so that individual cartridges and individual relays 8, 8' of individual line pairs can be controlled from a remote location.

To achieve this each electronic module 20 may have a network address that allows it to be addressed individually with data and/or commands as part of a network such as an themet network.

b) Provide selectable routing of power from the electronics module 20 to individual relays 8, 8' in a cartridge 25 for switching purposes to thereby allow line-by-line control of switching. This may be achieved by any suitable means. For example, a low-dropout regulator provides 5V for local use, and for forwarding to the other cartridges via a current-monitor circuit. This allows testing of the relay coils and also sensing the presence of the other cartridges. A small PlC microcontroller controls local relays and optionally the relays 8, 8' in the cartridge chain by basic PlC 110 lines. Busses may be provided to the relays 8, 8' in the cartridges via the connectors 12,22 and * ** * banks of controllable relays in the electronics module 20 may be used to *. S switch the power to one of the busses leading to one of the relays 8,8' in a selected cartridge. This relay bank may be controlled by basic FTC I/O lines.

c) Receive power from one or more line pairs connected to one of the cartridges on the terminal block on which the electronics module is attached. The power is received from a line pair through the contacts 26 and is transferred to the electronics module 20 via the connectors 12 and 22 for that cartridge.

By using spare telephone line pairs to provide power and/or control to the electronics module 20, there is no requirement to cable up the terminal blocks with additional control cables e.g. in the form of busses or network cables. This reduces the amount of cabling that needs to be done to provide the additional telephone services such as xDSL as the telephone cable pairs that are to be used for power and/or control are an integral part of the system.

d) Receive data and/or commands from a remote controller via one or more spare line pairs of one cartridge on the terminal block.

e) Provide optionally switching capabilities to switch an individual line pair of any of the cartridges to a test head or other service or equipment.

To provide these services the electronics module 20 is fed by power, e.g. DC power, along one or more of the telephone line pairs attached to one of the cartridges in the terminal block. For example, the first cartridge module of a terminal block (e.g. to be called a power supply cartridge) may be so constructed that a certain line pair is connected through the connector 12 of that cartridge and connector 22 on the electronics module to a power input of the electronics module 20. This line pair used for power supply can be a spare line pair not used for telephone services, for example. The other line pairs connected to this cartridge may be used for telephone services normally. The power connections from a line pair through connectors 12 and 22 may be permanent as long as that power cartridge is present in the terminal block 1. In an alternative embodiment the connections need not be permanent. Either in the electronic module 20 or in the power supply cartridge, controllable switching means e.g. latching relays may be provided that disconnect the power supply to the electronics module 20 from the line pair so that this line pair can then be used for telephone services, for example. For example, either the electronics module 20 or the power supply cartridge can contain a * small PlC microcontroller capable of handling RS485 communications and control of relays. A low-dropout regulator provides +5V power from an incoming +12V supply. **.*

This cartridge or the electronic module 20 has one or more relays controlled from PlC I/O lines for disconnecting the electronics module power line from the electronics module 20 to thereby disconnect the power to the electronics module 20. Alternatively the disconnection of the power to the electronics module may be done by manually operated relays, plugs or switches on the power supply cartridge or the electronic . module 20 or even the complete power supply cartridge can be removed and replaced with a new one not having the power supply feature. Once disconnected from its power supply the electronics module 20 is no longer of use (e.g. once the new service is up and running satisfactorily and all consumers are connected thereto) and can be disconnected and used elsewhere.

As the electronics module 20 need only be required when a new service has to be switched in or out for a customer it is not necessary for the electronics module 20 to be powered up all the time. It can be powered only just before a switching operation needs to be made.

The disconnectable components of a terminal block 1 are shown in Fig. 5. This shows a connector cartridge 25 in accordance with an embodiment of the present invention, and the electronics module 20 here shown as being made up of two parts -an electronics unit 23 that can be removed from the terminal block I and a connector module 24 that remains on the terminal block after removal of the electronics unit 23.

The electronics unit 23 may contain re-usable electronic components such as microcontrollers, relay banks, etc. whereas the connector module 24 need only include the connectors 22 and associated wiring.

Fig. 6 is a schematic representation of how power and/or data or commands may be provided to a terminal block 1 in accordance with a further embodiment of th present invention. The test heads 10, the test access matrix 9, the distribution frame and the terminal blocks 2, the lines 4, sub-racks 6 and the crossbar switch 11 are basically the same as has been described for Fig. 2. In addition a controller 30 is connected onto the cross-bar switch 11 that allows access of the controller 30 to any of the lines 4' that are to provide power to an electronics module 20 on one of the terminal blocks 1 of a distribution. The selectable switching capability of the test access matrix 9 is used in this embodiment to switch power and/or data or commands from the controller 30 to an individual one of the electronics modules 20 via one (4') of the line pairs 4. Once the power and/or data signals and/or command or control signals are connected through in * .* this way, the relevant electronics module 20 is powered up and can receive and process **** * * **. the data signals and/or command or control signals, e.g. to control the switching of one or more of the relays 8, 8' in a specific cartridge 25 on that terminal block to thereby * 15 connect in a new equipment and/or to disconnect legacy equipment for only that line pair. Optionally the controller may be integrated in or part of the test-head.

When retrofitting the present invention to existing terminal blocks 1 there may be insufficient space for locating the electronics module 20. In accordance with another embodiment of the present invention the electronics for control purposes housed in the electronic module 20 in previous embodiments may be located in one or more of the cartridges 25. As the power is received via the contacts 26 of one cartridge the electronics can be placed in this cartridge or spread over several cartridges. Fig. 7a is a schematic representation of the bank of cartridges 25 each having a shift register, relay drivers, and relay matrix with the last (or first for example) cartridge having a power supply and a microcontroller with connections to the TAM system 9 via one of the telephone lines. One of the cartridges 25 contains a small PlC microcontroller capable of handling RS485 communications and control of relays -see Fig. 7b. A low-dropout regulator provides +5V power from an incoming +12V supply. This cartridge will have oily the two relays for switching one of its lines. The drive circuitry for these relays is locally controlled from PlC I/O lines. The cartridge need only be powered up for short periods of time, when the TAM system 9 connects the controller 30 to it by setting up a connection to the line 4' (see Fig. 5). The remaining cartridges 25 on the terminal block can be "daisy chained" from the first cartridge using 5 connections:-a Shift-register serial clock (SL), Shift-register latch (LC), Data in/out of shift-registers (D), a Power Supply line (+5V) and a Ground line (OV). Each cartridge 25 contains a shift register and the drive circuitry for the required number of relays, e.g. up to 10 relays if there are contacts 26 for 5 line pairs. The shift register provides 8 parallel outputs which are used to control a 3 x 4 relay matrix -see Fig. 7c. This matrix is populated with the 10 relays required for the 5 cartridge lines plus a test load. This load is energised in order to check presence of the cartridge, the current being sensed by the circuit on the first (or last) cartridge. Connection from one cartridge 25 to the next can be by means of compression connectors, similar to those used for mobile phone batteries etc. Compression connectors on the top side of each cartridge 25 connect to metal pads on the underside of the next cartridge along. The cartridges 25 can be dove-tail moulded in plastic to insure adjacent cartridges interlock mechanically. * S.

Alternatively, (shown in Figs. 9a to c) a 5 way header 34 can be provided on S...

each cartridge 25. A passive multiconductor strip 36 connects all 20 cartridges 25 together on one terminal block I by plugging into each header 34.

The switching capabilities of any of the embodiments of the invention are shown schematically in Fig. 8. The lines lOOa and lOOb are connected to the subscriber line : *: : going out from the remote device or from the central office/exchange. Lines lOla and lOib are connected to the first signal path, e.g. to a legacy switch. Lines 102a and 102b are connected to the second signal path, e.g. the new electronic device such as a switch providing xDSL service. Reference numeral 103 refers to a block including the disconnect unit. An optional protection unit, e.g. overvoltage protection is shown as item 104. A connection to ground, e.g. pin 19, is given the reference number 105.

As shown in Fig. 8a and Sb the first state of the connector cartridge 25 (which depends on the sate of the relays 8, 8' as indicated above) can be either only connected to the first signal path, e.g. providing a POTS service or both first and second signal paths are provided. In the second state shown schematically in Fig. 8c only the second signal path, e.g. the new telecommunications service such as xDSL is provided. Fig. 8d is a further switching state in which all the connections are open.

Claims

Claims 1. Electrical switching apparatus for connection to a wiring terminal block of a distribution frame, the wiring terminal block being connected to a plurality of telephone lines, and cartridges inserted into the terminal block and a switching means in the cartridge for line-by-line switching, electrical power for powering the operation of the switching means being provided via one of the telephone lines connected to the wiring terminal block.
2. Apparatus according to claim 1, wherein the telephone line used for the electrical * power is provided via a line of a telephone cable connected to the wiring terminal, **.. whereby the other lines of the cable are for providing a telephone service and the **.* line used for the power supply is not used for a telephone service. * * * .
3. Apparatus according to claim 1 or 2, wherein the apparatus has a first pair of connection points for connecting a customer circuit, a second pair of connection points for connecting telecommunications exchange equipment and a third pair of * electrical connection points is provided for connecting further telecommunications equipment, the switching means having a first switching state in which the first pair of connection points is electrically connected to the second pair of connection points, and a second switching state in which the first pair of connection points is connected to the third pair of connection points.
4. Apparatus according to any previous claim, wherein the power supply to provide electrical power is a remote power supply that is selectably connected to the telephone line used to provide the electrical power by a test access matrix system.
5. Apparatus of claim 4, wherein the test access matrix system is adapted to connect lines used for a telephone service selectably to a test head.
6. Electrical switching apparatus for connection to a wiring terminal block for a distribution frame vaing a plurality of telephone lines connected thereto, comprising a first pair of connection points for connecting a customer circuit, a second pair of connection points for connecting telecommunications exchange equipment, and an earth connector optionally adapted to receive an overvoltage protection module, the first pair of connection points normally being connected to the second pair, and a third pair of electrical connection points for connecting further telecommunications equipment and switching means for line-by-line switching, the switching means having a first switching state in which the first pair of connection points is electrically connected to the second pair of connection points, and a second switching state in which the first pair of connection points is connected to the third pair of connection points, the switching means being powered via one of the telephone lines connected to the wiring terminal block.
7. Apparatus according to any previous claim, wherein the switching means is a relay. * *.
8. Apparatus according to any previous claim wherein the apparatus has an electronics : * module that is powered by electrical power supplied through the telephone line. * 15 **
9. Apparatus according to claim 8, wherein the electronics module is adapted to : *::* selectably route electrical power to the switching means. ** * * *.
10. Apparatus according to claim 8 or 9, wherein the electronics module is detachably connected to the wiring terminal block.
11. A telephone exchange incorporating electrical switching apparatus as defined in any of the previous claims.
12. A method of connecting new equipment to customer circuits on a line-by-line basis, which method comprises feeding electrical power to a terminal block of a distribution frame via a line of a telephone cable, and controlling switching of a switching means local to the terminal block remotely via a line of the telephone cable.
13. The method according to claim 12, wherein the switching means is changed from a first state into a second state, to thereby connect a customer circuit to new telecommunications equipment, and optionally to disconnect a customer circuit from legacy equipment.