GB2368487A

GB2368487A - Remote testing system

Info

Publication number: GB2368487A
Application number: GB0026071A
Authority: GB
Inventors: Alan Robert Perrett
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-10-25
Filing date: 2000-10-25
Publication date: 2002-05-01
Also published as: GB0026071D0

Abstract

Test apparatus (20) for installation by a telecommunication service provider, especially at a service user's premises (16), is disclosed. The test apparatus (20) is remotely operable by the telecommunications service provider to determine operational status information relating to the service provider's connection to the service user's site. (16) For example, the test apparatus may be operable to apply a test signal to the line that can be detected at a local office (10) of the service provider if the line is intact. The apparatus can also loop the line to enable its properties to be measured at the local office (10). Embodiments have particular applicability to testing a local loop (18).

Description

REMOTE TESTING SYSTEM

The present invention relates to a remote testing system. Particularly, but not exclusively, the invention relates to a testing system for a telecommunications installation, such as a public switched telephone network (PSTN).

Historically, telephone networks were owned and maintained by a telephone operator (PTT) that owned equipment within a customer's premises, as well as the local loop lines that connect each customer to the telephone network, and trunk lines. In the event that a customer's telephone service suffer a failure, there was a significant likelihood that the problem would have occurred as a result of a failure of equipment that belongs to the PTT. Therefore, a reasonable approach to fault detection and rectification was to assign an engineer to the'task of first locating and then rectifying the fault. The engineer could work on apparatus either outside or within the customer's premises, as required by the location of the fault.

As a result of developments within the telecommunications industry, equipment within a customer's premises that connects to the PSTN is commonly now neither owned by nor operated by a telecommunications services company that operates equipment external to the customer's premises.

Even in small domestic installations, an individual customer may own and be'responsible for telephone apparatus and wiring within their premises. Large commercial premises may contain a large array of complex equipment, none of which is the responsibility of any telecommunications services company. Therefore, a large

number of faults may arise that are not the responsibility of the telecommunications services company. However, it is that company that is most typically the customer's first point of contact in the event of a failure in the customer's telephone service. This can result in the telecommunications services company carrying out investigative work in cases where there is no fault in any equipment for which it is responsible.

An aim of this invention is to provide apparatus for testing telecommunications apparatus that can enable a telecommunications services company to attempt to establish whether a fault lies in equipment for which they are responsible, and thereby avoid dispatching an engineer to investigate a fault in equipment for which the company is not responsible.

Although some active components, such as network termination units and multiplexers now have some capability for remote fault diagnosis and testing, there is still much infrastructure that has no such capability, most notably copper infrastructure in the local loop.

Accordingly, from a first aspect, the invention provides test apparatus for installation by a telecommunication service provider at a remote location in a telecommunication network, the test apparatus being remotely operable by the telecommunications service provider to determine operational status information relating to the service provider's connection to the remote location.

This apparatus can enable the service provider to determine whether a fault lies at the remote location or in a connection to the remote location without having to send an

engineer to the remote location.

In a typical application, the remote location is a telecommunication service user's site. Such apparatus can enable the service provider to make a determination, at least in some cases, as to whether a reported failure is due to a fault in equipment for which it is responsible, or is beyond its responsibility within the service user's site.

Clearly, the invention has application where the service provider operates a PSTN, and the service user is a domestic or commercial user of the provider's services. In such cases, the apparatus can distinguish between a fault in the local loop and a fault in the service user's premises. However, the invention has wider application.

It may, for example, have application within a large corporate telecommunications network to assist in location of a fault within the network or by the service provider itself to locate a fault within its own network.

The invention has particular, but not exclusive, application where the connection to the remote location is an electrical loop. Typically, it is the local loop of a telecommunications service, and most typically, the local loop of an analogue or digital telephone service, or of an optical fibre connection.

The apparatus may be operable to apply an electrical signal to the connection. For example, the apparatus may include an oscillator that can apply an audio-frequency signal to the connection.

The apparatus may, additionally or alternatively, be operable to provide a continuous conductive (or other

applicable) path through the connection. This is typically referred to as"looping the line".

In embodiments intended for use in a domestic installation, the apparatus may be connected to just one line. However, in more complex applications, the apparatus may be operable selectively to test a plurality of connections.

There are many alternative possible arrangements by which a user can communicate with the remote testing apparatus.

In preferred single line embodiments, the apparatus is operative to receive and respond to a radio signal transmitted on a pager network. Alternative or additional interfaces may be provided including ISDN, PSTN or cellular modems, local area network connections, and derived access.

Advantageously, apparatus embodying the invention may communicate with a user though a computer terminal. For ease of operation, it may include a menu-driven user interface.

From another aspect, the invention provides a method of locating a fault in a telecommunications installation comprising remotely activating test apparatus at a remote location in the telecommunications installation, and monitoring the effect of the test apparatus on the telecommunications installation.

Typically, the remote location may be a telecommunication user's premises.

For example, a method embodying the invention may include application of a signal to a communications link at a remote location and monitoring reception of that signal at a central office of the telecommunications service

provider.

Embodiments of the invention will now be described in detail, by way of example, and with reference to the accompanying drawings, in which: Figure 1 is a representation of a local loop connection between a local office of a telecommunications service provider and a customer's premises; Figure 2 is a block diagram of remote testing apparatus embodying the invention; Figures 3A and 3B are flow diagrams representing the operation of the apparatus of Figure 2; Figure 4 is a block diagram of testing apparatus being a second embodiment of the invention; Figure 5 is a diagram of components of the apparatus of Figure 4; Figure 6 is a flowchart showing major steps in operation of the apparatus of Figures 4 and 5; Figure 7 is an example of a main menu display of apparatus embodying the invention; and Figure 8 is an example of a test menu display of apparatus embodying the invention.

With reference first to Figure 1, an overview of a typical telephone installation will be described.

In order to provide a PSTN telephone service to a customer,

a telecommunications service provider has a local office 10. The local office 10 is connected to a trunk telecommunications network 12. Switches (not shown) are provided within the local office 10 to provide a switched connection between the trunk telecommunications network 12 and an individual customer's line termination equipment 14. The customer's line termination equipment 14 is connected to the customer's premises 16 by a copper wire pair 18 known as the"local loop"which may include aerial or underground cable. Within the customer's premises 16, the local loop 18 is terminated at a line termination unit 20. Copper wire pairs 22 extend from the line termination unit 20 to outlet points, such as a telephone socket 24, to which the customer can connect suitable apparatus 26.

In the above-described installation, the service provider is typically responsible for maintaining all equipment up to and including the line termination unit 20. Further equipment within the customer's premises is typically the customer's own responsibility.

In an installation being a first embodiment of this invention, additional remote testing apparatus is installed within or in the vicinity of the termination unit 20, for example, within a standard CPE wiring case. The remote testing apparatus can be remotely controlled from the local office 10 (or elsewhere) by the service provider's engineering staff in order to generate test signals that can be detected by suitable equipment in the local office 10. By analysing the signals received at the local office 10 it is possible to obtain diagnostic information relating to the condition of the local loop 18.

An example of remote testing apparatus suitable for use in the above-described installation will now be described with

reference to Figure 2.

Remote testing apparatus is contained within a line termination unit 20 installed in the customer's premises. The line termination unit is connected to the local loop with a first pair of connections 32 that connect with the copper pair from the local office. A second pair of terminals 34 connect the line termination unit 20 to cabling within the customer's premises.

The line termination unit 20 includes line termination components 36, substantially similar to components provided in a conventional line termination unit. An output pair of the line termination components 36 is connected to the second pair of terminals 34, and an input pair of the line termination components 36 is connected to the first pair of connections 32. Under normal conditions of operation, the line termination components 36 are connected to the local loop 18. In this condition, the line termination unit 20 functions in a conventional manner to provide the customer with a telephone service.

The input pair of the line termination components 36 is connected to a third pair of connections 42.

In this embodiment, the third pair 42 is connected, through a DC isolation unit 44 and a resistor 46 to an oscillator 48, and the control input 49 is connected to an output of a processor 50. The processor 50 has an input line 52.

The input line is connected to a pager unit 54 and to a manual control 56. In this embodiment, when activated by a control signal received through the control input 49, the oscillator 48 generates a 1kHz, OdBm signal.

The apparatus further comprises a loop switch 57. The loop

switch 57 has a pair of inputs 58 that are connected to the input pair. The loop switch 57 also has a control input 59 that is connected to an output of the processor 50. The processor 50 can apply a control signal to the control input 59, which then causes the loop switch to interconnect its inputs 58, with the effect that a closed circuit is formed between the input pair.

Operation of the apparatus of Figure 2 will now be described with reference to the flow diagrams of Figures 3A and 3B.

During normal operation of the customer's telephone service, the processor 50 remains inactive and the line termination components 36 are connected to the local loop 18.

In the event that the customer reports a fault, a test procedure is initiated by the telecommunication service provider, as illustrated in Figure 3A.

In first step 60, the service provider accesses a pager service to transmit a radio pager signal that can be received by the pager unit 54 of the apparatus. A signal is then transmitted at step 62 that includes a pager number for the apparatus to be tested. At step 64, the pager number is tested for acceptability. If the number is accepted, then a response is awaited from the remote testing apparatus at step 68. On the other hand, if the number is not accepted, the session is abandoned (step 66).

The corresponding steps carried out by the remote testing apparatus is illustrated in Figure 3B.

When a paging signal is received at step 70, the pager unit

54 applies an alerting signal to the input line 52 of the processor 50. A two-stage testing process is then started. In the first stage, the processor 50 applies a signal to the control input 49 of the oscillator 48, so that the oscillator 48 becomes activated and generates a 1kHz test signal that is transmitted through the resistor 46 and the DC isolation unit 44, to the local loop 18 (step 72). After a predetermined time, the microprocessor 50 removes the signal from the control input 49 to stop the test signal and completer the first testing phase.

In the second phase, the processor 50 sends a control signal to the loop switch to open and close the loop a predetermined number of times.

Finally, the processor 50 closes down, and returns the line to normal operation (step 74).

During step 72, apparatus in the central office (which may be automated or manually operated) is applied to detect the signal generated by the oscillator 48. If this is absent, then there is a strong likelihood that there is a fault in apparatus that belongs to the service provider, for example, as a result of an open-circuit fault in the local loop 18. However, if the 1kHz signal is detected at the local office, then it can be assumed that the local loop 18 is at least partially conductive. During the second phase of the test, the total resistance, capacitance and other properties of the loop can be measured at the local office.

The quality of the signal and of the loop can then be analysed to determine whether it is properly operational.

If it is, then the service provider can assume that the fault is most likely to lie within the customer's premises, and further investigation may be warranted before an engineer is assigned to the fault.

Operation of the manual control 56 will likewise initiate the sequence of operation described with reference to Figure 3B. This can be used in the event that the pager system fails to communicate successfully with the remote testing apparatus.

The above-described remote testing apparatus has application to testing a single line. Apparatus embodying the invention can be provided for use with more complex, multiple line installations, as will now be described.

With reference to Figures 4 and 5, apparatus embodying the invention can be employed to test multiple lines serving a customer's premises. Such apparatus operates with the same underlying principle as that described above, in that it tests a line by carrying out a test procedure at the customer's premises, so that the effects of the test procedure can be detected at the local office. In this embodiment, additional control can be effected over the signals generated by the apparatus, and additional control interfaces can be provided for use by the central office for communication with the apparatus.

In this example, the remote testing apparatus 80 can connect to any number of local loop pairs 82, up to a predetermined maximum (for example, 30). Internally of the apparatus, each line pair is connected to a respective switch module 84. The apparatus 80 includes a test signal bus 86 that is connected to each of the switch modules 84.

Each switch module 84 has a control input 88, and is operative such that application of a control signal to the control input 88 causes the corresponding line pair to become connected to the test signal bus 86.

Test modules are additionally connected to the test signal

bus 86 through respective switch modules 84'. Such test modules might include (amongst other possibilities) an oscillator 90, a loop control 92, or an external connection that can be used with an optional test unit 94. Each switch module 84'has a control input 88'operable to connect the test module to the test signal bus, as described above.

Each control input 88, 88'is connected to a control bus 100 that is driven by the output from a processor 102. The processor 102 is programmed to ensure that any one line pair can be connected to the test signal bus 86 at any time, and that one or more test modules can be connected to the test signal bus 86, as required.

In this embodiment, the processor has a serial interface 104 and executes software operative to run a terminal session on the serial interface 104. A computer can be connected to the interface 104 to enable an operator to communicate with the testing apparatus 80 by means of terminal emulation software.

The processor also communicates with an external interface unit 106 to implement remote access to the apparatus. The interface unit 106 can communicate with a plurality of access circuits 108 including, for example, a PSTN line, an ISDN line, a cellular modem, derived access from spare capacity in the customer's local loop lines or network access from a customer's local area network. Depending upon the installation, one or more suitable access circuits will be implemented.

A PSTN line implements remote access to the testing apparatus through a modem connection to a remote computer. ISDN access can offer the same facility, and its higher

speed can enable the apparatus to be monitored in real time. Installation of a cellular modem makes the testing apparatus 80 very resilient in that it is still possible to communicate with it in the event that all fixed links to the site become inaccessible.

Operation of the testing apparatus will now be described with reference to Figure 6.

When a user first connects to the apparatus (step 120), by whatever interface is chosen, the system first prompts the user to enter a username and password 122. These are checked for acceptability 124 and the session is terminated 126 unless they are found to be valid.

The system then displays a channel menu 128 (an example is shown in Figure 7). This invites a user to enter a number to identify the line to be tested 130. The system displays a test menu 132 (see, for example, Figure 8). This allows a user to select which test to apply to the line. Such test might include, for example, application of a tone or looping the line. The selected test is then applied 134, 136 for a predetermined time, after which the test is cleared 138.

The test is applied by the microprocessor applying signals to the control bus 100 to select the switches 88,88' corresponding to the line 82 and test module selected by the user.

The menu selection 0 in the channel menu will normally be used to select a sub menu which can control a module which for example, could loop the site link (fibre/coax/etc. ) or it could be used to activate a loop on a modem or other device. It can easily be configured to be another normal

interface. The optional modules can be added the apparatus to tailor the system to particular requirements.

A modification to the apparatus may be provided for systems to be used in a site in which multiple services are delivered over a single fibre 112. The fibre network termination unit (NTU) 110 provided by the service provider will normally be operable in a range of testing modes.

However, loss of connection in the fibre 112 will prevent access to the system for use of the testing modes. To overcome this problem, the apparatus is optionally provided with a remotely-accessible interface unit 114.

The interface unit 114 can be programmed, as required, automatically to loop the fibre link, or to initiate a terminal session with the NTU 110. This can be used to diagnose remotely the state of the fault in the network link without the need to send an engineer to the site.

Additional add-on modules can be provided for a particular application (such as a fibre, ADSL, digital or other link) with a suitable interface for the relevant NTU.

An example of the system in use will now be described.

A PSTN user reports no dial tone on their PSTN line.

Conventional line test facilities prove the fault to be outside the serving exchange. The circuit is then intercepted in the telephone exchange by normal testing facilities and is available for audio monitoring.

The remote testing unit at the customer's premises is accessed and a tone selected for the correct line. The tone is not heard at the telephone exchange. This test is repeated at the customer's premises end with the customer

listening to the phone handset. The customer reports that they can hear the tone. The fault is thus proved off the customer's premises and onto the service provider's line plant. This diagnosis can be confirmed if the testing unit is instructed to loop the line. If the line remains opencircuit at the local office then this again suggests that the fault lies off the customer's premises. This simple example demonstrates how the testing apparatus replaces an on-site engineer.

Alternative embodiments of the invention may be capable of accepting inputs from other alarm type devices (air conditioning, alarm etc) and triggering a call to another site to report a problem.

Moreover, the invention is not restricted to application at a customer's site. It can also be used to test the integrity of various parts of a telecommunication network. For example, suitable remote testing apparatus embodying the invention could be installed at an unstaffed local exchange to test the link between that exchange and a central office prior to sending an engineer to the local exchange to investigate a fault.

Claims

1. Test apparatus for installation by a telecommunication service provider at a remote location in a telecommiunication network, the test apparatus being remotely operable by the telecommunications service provider to determine operational status information relating to the service provider's connection to the remote location.

2. Test apparatus according to claim 1 in which the remote location is a telecommunication service user's site.

3. Test apparatus according to claim 1 or claim 2 in which the connection to the service user's site is an electrical loop.

4. Test apparatus according to claim 3 in which the electrical loop is the local loop of a telecommunications service.

5. Test apparatus according to claim 4 in which the local loop provides an analogue telephone service.

6. Test apparatus according to any preceding claim operable to apply an electrical signal to the connection.

7. Test apparatus according to claim 6 in which the electrical signal is an audio-frequency signal.

8. Test apparatus according to any preceding claim operable to provide a continuous conductive path through the connection.

9. Test apparatus according to any preceding claim

operable selectively to test a plurality of connections.

10. Test apparatus according to any preceding claim operative to receive and respond to a radio signal transmitted on a pager network.

11. Test apparatus according to any preceding claim comprising one or more interfaces including ISDN, PSTN or cellular modems, local area network connections, and derived access interfaces.

12. Test apparatus according to any preceding claim operative to communicate with a user though a computer terminal.

13. Test apparatus according to claim 12 including a menu-driven user interface.

14. Test apparatus substantially as herein described with reference to the accompanying drawings.

15. A method of locating a fault in a telecommunications installation comprising remotely activating test apparatus in a remote location of the telecommunications installation, and remotely monitoring the effect of the test apparatus on the telecommunications installation.

16. A method according to claim 15 in which the remote location is a telecommunication user's premises 17. A method according to claim 15 or claim 16 in which a signal is applied to a communications link at a customer's premises and reception of that signal is monitored at a central office of the telecommunications service provider. 18. A method according to any one of claims 15 to 17 in which the remote location is at a customer's premises.

19. A method substantially as herein described with reference to the accompanying drawings.

Amendments to the claims have been filed as follows

1. Test apparatus for installation by a telecommunication service provider at a remote location in a telecommunication network, the test apparatus being remotely operable by the telecommunications service provider to determine operational status information relating to the service provider's connection to the remote location, the apparatus being operable using a communications medium other than the connection being tested.

2. Test apparatus according to claim 1 wherein the communications medium includes radio signals transmitted on a pager network.

3. Test apparatus according to claim 1 or 2 wherein the communications medium includes at least one of the following types of interfaces: ISDN, PSTN or cellular modems, local area network connections, and derived access.

4. Test apparatus according to any one of the preceding claims which can send an electrical signal from the remote location to the telecommunications service provider via the connection being tested.

S. Test apparatus according to claim 4 wherein the apparatus sends the signal from the remote location in response to a signal sent by the telecommunications service provider via the communications medium.

6. Test apparatus according to any one of the preceding claims operable to provide a continuous conductive path through the connection.

7. Test apparatus according to any one of the preceding claims operable selectively to test a plurality of connections.

8. Test apparatus according to any one of the preceding claims operative to communicate with a user though a computer terminal.

9. Test apparatus according to claim 8 including a menu-driven user interface.

10. Test apparatus according to any one of the preceding claims in which the remote location is a telecommunication service user's site.

11. Test apparatus according to any one of the preceding claims in which the connection to the service user's site is an electrical loop.

12. Test apparatus according to claim 11 in which the electrical loop is the local loop of a telecommunications service.

13. Test apparatus according to claim 12 in which the local loop provides an analogue telephone service.

14. Test apparatus according to any one of the preceding claims operable to apply an electrical signal to the connection.

15. Test apparatus according to claim 14 in which the electrical signal is an audio-frequency signal.

16. Test apparatus substantially as herein described with reference to the accompanying drawings.

17. A method of locating a fault in a telecommunications installation comprising remotely activating test apparatus in a remote location of the telecommunications installation using a communications medium other than the connection being tested, and remotely monitoring the effect of the test apparatus on the telecommunications installation.

18. A method according to claim 17 wherein the communications medium includes radio signals transmitted on a pager network.

19. A method according to claim 17 or 18 wherein the communications medium includes at least one of the following types of interfaces: ISDN, PSTN or cellular modems, local area network connections, and derived access interfaces.

20. A method according to any one of claims 17 to 19 in which a signal is applied to a communications link at a remote location and reception of that signal is monitored at a central office of the telecommunications service provider.

21. A method according to claim 20 in which the remote location is a telecommunication user's premises

22. A method according to any one of claims 17 to 21 in which the remote location is at a customer's premises.

23. A method substantially as herein described with reference to the accompanying drawings.