ZA200505021B

ZA200505021B - Remote actuated line testing

Info

Publication number: ZA200505021B
Application number: ZA200505021A
Authority: ZA
Inventors: Ivan T Popv
Original assignee: Cz Mfg Pty Ltd
Priority date: 2005-06-21
Filing date: 2005-06-21
Publication date: 2006-04-26

Description

4 FIELD OF THE INVENTION

This invention relates to the field of telecommunications, including both data and voice communication over land lines in general, and more specifically to a remote line access testing device. Examples are ADSL, xDSL, ISDN, T1 and E1 lines for computer communication using modems at the line terminations.

BACKGROUND TO THE INVENTION

A service provider such as a nation-wide telephone line provider has to respond to service complaints and problems of consumers of the service, who usually are not technically competent to analyse the problem. The service provider must send a technician to the consumer's address so as to test the telecommunications line running from a service provider (such as a telephone utility company) to an end-user. This is the problem associated with such testing, that it generally requires a technician to manually connect testing equipment to the line at a point where the line is connected to the end- user's equipment in order to determine if a fault is on the line or if the end-users equipment is faulty. The premises may not be open to those wishing to test lines and equipment, or the premises may be open but a distance away and considerable cost in manpower, transport, time and money is caused in order to visit them.

The main problem is a huge and uneconomic manpower requirement, since a technician is required to examine the line at the end user's premises.

SUMMARY OF THE INVENTION

According to the invention there is provided a remote line testing device which includes : - a line interface for connecting the device to an existing telecommunications line having at least two wires;

- a network interface for connecting the device to a telecommunications network of a user; - switching means connected to the line interface, which switching means is b configured to disconnect the device from the telecommunications line or to connect the wires of the telecommunications line in a short circuit or to perform a loop back for a four wire circuit in order to facilitate the testing of the line's capacitance, isolation or the continuity of the wires, respectively, when in use; - a decoupler, which includes an electrical transformer having primary and secondary windings, which primary windings are connected to the switching means, which primary and secondary windings both include a series connected capacitor, the decoupler further including two resistive impedances each separately bridging a terminal of the primary winding capacitor with that of the respective secondary winding capacitor; and - control means, which is arranged to draw electrical energy across the primary winding capacitor, in use, which control means is configured to recognize a test signal on the telecommunications line and to control the switching means according to the recognized test signal, to allow remote testing of the telecommunications line.

The resistive impedances provide a path for DC current to flow across the transformer, when applicable, the capacitors in turn allowing AC communication signals to propagate across the transformer.

The line interface may include connection terminals to which the telecommunications line is connected, in use. Accordingly, the line interface may include a corresponding number of connection terminals for the number of wires present in the line, e.g. two separate terminals for two wires, four terminals for four wires, or the like.

The network interface may include connection terminals to which the network of the user is connected to, in use. Accordingly, the network interface may include a corresponding number of connection terminals for the number of wires present in the line, e.g. 2 wires, 4 wires, or the like.

The switching means may include a latching relay. The switching means may include a semi conductor component connected in parallel with the latching relay. The semi conductor component may include a MOSFET (Metal Oxide Semiconductor Field Effect

Transistor), or the like. be The decoupler may include two separate transformers each having a primary and

S secondary winding which two transformers are connected so that the two respective primary windings are connected via a capacitor to represent a single primary winding and the two respective secondary windings are connected via a capacitor to represent a single secondary winding.

It is to be appreciated that the transformer's winding ratio is generally determined to facilitate the propagation of the AC communication signal.

The impedances providing a path for DC current to flow across the transformer may include only resistors.

The control means may include an electrical energy storage means. The storage means may include a capacitor, e.g. a Supercapacitor, or the like. The storage means may include an electrochemical cell.

The control means may include logic circuitry such as filters, operational amplifiers, and decoders which are configured and arranged to recognize the test signal and control the switching means.

The control means may be configured to monitor a predetermined frequency range to recognize the test signal, i.e. the test signal has a predetermined frequency and/or other characteristics which the control means monitors.

The control means may include a manual override configured to allow a person to manually control the switching means.

The device may include surge protection circuitry to protect the device from electrical surges, e.g. lightning, or the like.

The device may include an independent power connection which is configured to provide the storage means with electrical power in order to power the control means.

BRIEF DESCRIPTION OF THE DRAWINGS

Ny The invention is now described, by way of non-limiting example, with reference to the accompanying drawings wherein : -

Figure 1a and 1b show, diagrammatically, a preferred connection location of a remote line testing device, in accordance with the invention;

Figure 2 is a schematic representation of the broad principle of the invention,

Figure 3 shows, diagrammatically, the remote line testing device shown in Figure 1and 2;

Figure 4 shows, diagrammatically, switching means as shown in Figure 2; and

Figure 5 is a graph of events against time, being a timing diagram of the operation of the remote line testing device shown in Figure 2. :

DETAILED DESCRIPTION OF THE INVENTION

With reference to the accompanying drawings, a remote line testing device, in accordance with the invention, is generally indicated by reference numeral 10.

Referring to Figure 1, the device 10 is shown connected to a telecommunications line 12. lt is to be appreciated that the line 12 can include any number of wires, depending on the application of the line 12. The embodiments shown have two and four wires, respectively.

It is further to be appreciated that the device 10 is able to be applied to different lines having different numbers of wires by merely configuring the device 10 to interface with more wires along the general concept of the invention.

As shown, the device 10 is connected between a telecommunications line 12 running from a service provider 14, such as a telephone company, or the like, to telecommunications network terminating equipment 16 of an end-user. Accordingly, the x line 12 typically supplies the network 16 with a connection to a service provided by the service provider 14, such as telephony, network access, and/or the like. As such, the line 12 can be a telephone line, an ISDN line, an ADSL line, and/or the like.

It is to be appreciated that the device is installed in the line 12 at a point where the telecommunications line 12 ends and the network 16 begins, i.e. the device 10 demarcates the end of the line 12. This is due to the fact that the service provider 14 is generally only responsible for maintaining the line 12 and not the network 16 of the user.

As shown further in figure 2, the device 10 broadly includes a switching circuit 22, and ac-dc coupling/decoupling signal unit 24 and control logic 26.

Referring now to Figure 3, the device includes a line interface 18, a network interface 20, switching means 22, a decoupler 24, and control means 26.

The line interface 18 is for connecting the device 10 to the telecommunications line 12 which has at least two wires. Accordingly, the line interface 18 generally includes connection terminals to which the wires of the telecommunications line 12 are connected, in use. As such, the line interface 18 includes a corresponding number of connection terminals for the number of wires present in the line 12, e.g. two separate terminals for two wires, four terminals for four wires, or the like.

The network interface 20 is for connecting the device 10 to the telecommunications network terminating equipment 16 of an end-user. Accordingly, the network interface 20 generally includes connection terminals to which the network terminating equipment 16 of the end-user is connected to, in use. As such, the network interface 20 includes a corresponding number of connection terminals for the number of wires present in the line 12, e.g. two terminals for two wires, four terminals for four wires, or the like.

The switching means 22 is connected to the line interface 18. The switching means 22 is configured to disconnect the device 10 from the telecommunications line 12, or to connect the wires of the telecommunications line 12 in y} a short circuit or in loop back mode for four wire applications in order to facilitate the testing of the line's capacitance, isolation or the continuity of the wires, respectively, when in use.

Referring now to Figure 4, the switching means 22 includes a latching relay 28 and a semi conductor switch 30 arranged in parallel with the relay 28. The latching relay 28 is typically used, as a normal relay generally requires more power to operate than is available. A latching relay can be opened or closed and requires no power to remain in a particular state.

The semi conductor switch 30 provides redundancy to the switching relay 28, as the semi conductor switch 30 is able to provide an electrical path should the relay 28 not function correctly. It is to be appreciated that a semi conductor switch is used due to the fact that it requires a low energy operate.

Referring again to Figure 3, the decoupler 24 includes an electrical transformer 32 which has primary and secondary windings 34.1 and 34.2, respectively. The primary winding 34.1 is connected to the switching means 22. As shown, both windings 34 include a capacitor 36.

The decoupler 24 further includes two impedances 38 each separately bridging a terminal of the primary winding capacitor 36.1 with that of the respective secondary winding capacitor 36.2 to provide a path for DC current to flow across the transformer 32. The capacitors 36.1 and 36.2 allow AC communication signals to propagate across the transformer 32 with minimal interference. tis to be appreciated that the decoupler 24 typically includes two separate transformers each having a primary and secondary winding which two transformers are connected so that the two respective primary windings are connected via a capacitor to represent a single primary winding and the two respective secondary windings are connected via a capacitor to represent a single secondary winding. This configuration offers a simple practical configuration.

It is also to be appreciated that the transformer's 32 winding ratio is generally determined to facilitate the propagation of the AC communication signal across the ~R decoupler 24 according to general electronic design principals.

The impedances 38 providing a path for DC signals are typically resistors, as shown, but may include other forms of combined impedance.

The control means 26 is typically arranged to draw electrical energy from the primary winding capacitor 36.1. The control means is also configured to recognize a test signal on the telecommunications line 12 and to control the switching means 22 according to the recognized test signal, to allow remote testing of the telecommunications line 12.

The control means 26 generally includes an electrical energy storage means (not shown). In a preferred embodiment of the invention, the storage means 26 includes a capacitor, e.g. a Supercapacitor, or the like. It is to be appreciated that the storage means 26 may also include an electrochemical cell.

The control means 26 generally includes logic circuitry such as filters, operational amplifiers, and decoders which are configured and arranged to recognize the test signal and control the switching means 22.

As such, the control means 26 is typically configured to monitor a predetermined frequency range to recognize the test signal, i.e. the test signal has a predetermined frequency and/or other characteristics which the control means 26 monitors.

In addition, the control means 26 may also include a manual override (not shown) which is configured to allow a person to manually control the switching means 22.

In further embodiments of the invention (not shown), the device 10 includes surge protection circuitry to protect the device 10 from electrical surges, e.g. lightning, or the like. In addition, the surge protection circuitry may also be configured to protect the user's network 16 from electrical surges.

The device 10 may further include an independent power connection (not shown) which is configured to provide the electrical storage means and/or control means 26 with electrical power in order to power the control means when no power is available. x

In use, the device is connected in the line 12 between the service provider 14 and the end-user's network 16. The device 10 provides minimal resistance to any AC communications signals normally found on the line 12, whilst also providing a path for

DC current to the network terminating equipment 16 when it is required. As such, the device 10 seeks to be “invisible” to signals propagating on the line 12.

Under normal operation, the control means 26 includes the electrical storage means in the form of a capacitor which is able to store electrical energy for an extended period of time. As such, the capacitor is typically a Supercapacitor. The Supercapacitor is charged from the voltage across the capacitor 36.1 of the primary winding 34.1.

Accordingly, the Supercapacitor can be charged by imposing a current limited voltage source on the line 12. This current allows the Supercapacitor to store energy.

Accordingly, the device 10 does not rely on an electricity supply from the end-user 16.

With reference to Figure 5, the control means 26 is configured to monitor the line interface 18 for signals. Figure 4 shows a general timing diagram for a test sequence on the line 12. The y-axis shows the signals and the x-axis shows the progression of time.

To test the line 12, a pulse 42 is firstly imposed on the line 12 by the service provider 14. This pulse is typically a 48 volt DC limited to 50mA signal for energizing the

Supercapacitor of the control means 26. Thereafter a short pulse 44 is the test signal and generally has a specific frequency which the control means 26 interprets as a predetermined instruction. Thereafter a wait time 46 is introduced before the requested test 48 has been activated. The wait period allows enough time for the test equipment from the service provider 14 to be connected.

The Inventors regard it as an advantage that the device allows remote testing of telecommunication lines without requiring a technician to visit a remote site. The

Inventors regard it as a further advantage that the device draws power from the telecommunications line directly without requiring an external power source. The

Inventors regard it as a further advantage that the deicB if) applicable: to} glifherous different communication lines with minor modifications to the device. 2

The Inventors regard it as a further advantage that the device includes switching means which has redundancy for reliability. The Inventors regard it as yet a further advantage that the device does not adversely influence the quality of the line. --=--------000-----------

Claims

1. A remote line testing device which includes : - ¥) - a line interface for connecting the device to an existing telecommunications line having at least two wires; - a user interface for connecting the device to a telecommunications network terminating equipment of a user; - switching means connected to the line interface, which switching means is configured to disconnect the device from the telecommunications line or to connect the wires of the telecommunications line in a short circuit or loop back in order to facilitate the testing of the line's capacitance, isolation or the continuity of the wires, respectively, when in use; - a decoupler, which includes an electrical transformer having primary and secondary windings, which primary windings are connected to the switching means, which windings both include a capacitor, the decoupler further including two resistive impedances each separately bridging a terminal of the primary winding capacitor with that of the respective secondary winding capacitor; and - control means, which is arranged to draw electrical energy from the primary winding capacitor, in use, which control means is configured to recognize a test signal on the telecommunications line and to control the switching means according to the recognized test signal, to allow remote testing of the telecommunications line.

2. A device as claimed in claim 1, wherein the line interface includes connection terminals to which the telecommunications line is connected, in use.

3. A device as claimed in either one of claims 1 or 2, wherein the network interface includes connection terminals to which the network of the user is connected to, in use.

4. A device as claimed in any one of claims 1 to 3, wherein the switching means includes a latching relay.

5. A device as claimed in claim 4, wherein the switching means includes a semi conductor connected in parallel with the latching relay.

6. A device as claimed in claim 5, wherein the semi conductor includes a semi conductor switch.

y 7. A device as claimed in any one of claims 1 to 6, wherein the decoupler includes one or two separate transformers, each having a primary and secondary winding, which two transformers are connected so that the two respective primary windings are connected via a capacitor to represent a single primary winding and the two respective secondary windings are connected via a capacitor to represent a single secondary winding.

8. A device as claimed in any one of claims 1 to 7, wherein the impedances bridging the capacitors of the respective windings include only resistors.

9. A device as claimed in any one of claims 1 to 8, wherein the control means includes an electrical energy storage means.

10. A device as claimed in claim 9, wherein the electrical storage means includes a capacitor.

11. A device as claimed in claim 9, wherein the electrical storage means includes an electrochemical cell.

12. A device as claimed in any one of claims 1 to 11, wherein the control means includes logic circuitry configured to recognize the test signal and control the switching means.

13. A device as claimed in any one of claims 1 to 12, wherein the control means is configured to monitor a predetermined frequency range in order to recognize the test signal on the telecommunications line.

14. A device as claimed in any one of claims 1 to 13, wherein the control means includes a manual override configured to allow a person to manually control the switching means.

15. A device as claimed in any one of claims 1 to 14, which includes surge protection circuitry to protect the device from electrical surges. <

16. A device as claimed in any one of claims 1 to 15, which includes an independent power connection to provide the electrical storage means with electrical power in order to power the control means.

17. A device as claimed in any one of claims 1 to 16, in which the impedances bridging the primary and secondary windings of the transformer are resistive impedances.

18. A device as herein described and illustrated in any one or more of the drawings.

19. A new device substantially as herein described. memmmmemo-=-000------------ DATED THIS 21st JUNE 2005 J & 13 Ji APPLICANTS he his