SERVICE

Field of the Invention

The present invention is generally related to the provision of data communication networks and more particularly to methods and systems for migrating from a first service connecting a subscriber to an exchange to a second service connecting the subscriber to a fibre access node. Background to the Invention

Developments in digital technology are opening up new ways to deliver content, including digital TV and Internet Protocol TV. However, to date most broadband subscribers have relied on digital subscriber line (DSL) or cable modem connections which provide insufficient speeds for deployment of advanced multimedia applications. Accordingly, the greater access speeds provided by locating the fibre access nodes closer to the subscriber premises are proving increasingly attractive.

Fibre access nodes may be located at various points between the exchange and the customer's premises including cross-connect facilities (CCF) such as pillars, cabinets, pits, and main distribution frames (MDF). Hence various terms are commonly used to describe fibre access nodes including examples such as fibre to the node (FTTN), fibre to the cabinet (FTTCab), fibre to the kerb (FTTK), fibre to the distribution point (FTTdp), fibre to the building (FTTB), fibre to the home (FTTH), optical network units (ONU) and optical network terminals (ONT). The term FTTx node will be used interchangeably with the term fibre access node herein but does not limit the application of the present invention to any specific FTTx architecture per se.

A typical configuration of combined digital subscriber line (DSL) and plain old telephony service (POTS) delivery is shown in Figure 1 . POTS 4 are delivered from a local exchange 1 via a low pass filter 5 and interconnected with DSL services delivered from a digital subscriber line access multiplexer (DSLAM) 2 via a high pass filter 3. The line connection from the exchange 6 typically connects to subscriber premises 12 via a cross-connect facility (CCF) 10 which may be located in a street-side cabinet or "pillar".

The line connection from the exchange 6 and the line connection from the subscriber premises 1 1 both terminate at the CCF 10 on termination blocks 7a & 7b respectively. A jumper line 8 interconnects the termination blocks 7a & 7b to complete the connection between the exchange 1 and the subscriber premises 12. At the subscriber premises 12, the subscriber line 1 1 connects to a DSL modem 14 via a high pass filter 13 and telephony equipment or POTS 16 via a low pass filter 15.

Some methods have been proposed for migrating subscribers to FTTx nodes (referred to as "pillar migration"), including the "flash-cut" procedure which involves disconnecting the line connecting the exchange with the subscriber premises, to enable connection of the subscriber premises to the FTTx node; and the "relay-based" procedure which involves connecting a relay matrix between a copper pair connected to the subscriber premises and a copper pair connected to the exchange, and disconnecting the jumper line connecting the exchange with the subscriber premises, enabling the connection to the subscriber premises to be switched between the exchange and the fibre node.

Problems with existing pillar migration solutions arise due to the large number of cross-connect facilities or pillars involved in FTTx node deployments, which lead to significant labour costs incurred in migrating connections from the exchange to the FTTx node. Moreover, the proposed relay-based procedure further involves the use of relay matrix equipment and additional copper pair connections thereby increasing the equipment and material costs involved in deployment and maintenance.

A reference herein to matter which is given as prior art is not to be taken as an admission that that document or matter was known or that the information was part of the common general knowledge as at the priority date of any of the claims. Summary of the Invention

According to an aspect of the present invention, there is provided a method for migrating at least one of a plurality of subscribers from a first service connecting the subscriber to an exchange to a second service connecting the subscriber to a FTTx node, the subscriber being connected to the first service via a subscriber line, the method including the following steps:

(a) establishing a connection between the FTTx node and the subscriber line at a node connection point;

(b) establishing a connection between the FTTx node and the exchange at the node connection point; and

(c) remotely activating the first service at the exchange and deactivating the second service at the FTTx node, or remotely deactivating the first service at the exchange and activating the second service at the FTTx node; wherein the subscriber remains physically and simultaneously connected to both the FTTx node and the exchange at all times.

The first service typically includes at least a broadband service, e.g. a digital subscriber line (DSL) but may include a DSL in combination with a narrowband service, e.g. plain old telephony service (POTS) delivered from a local exchange or central office (CO). The first service may also be a legacy service such as SHDSL, ISDN, E1/T1 . The line connection from the exchange to the subscriber will typically occur via a CCF located in a street-side cabinet or "pillar" or similar interconnection point such as a pit, or main distribution frame (MDF).

The second service provides access to a FTTx node using optical fibre rather than the usual copper pair connection employed by the first service. The line connection from the FTTx node to the subscriber occurs at the node connection point.

Whilst the FTTx node may include POTS, as herein described, it is to be understood that the inclusion of POTS is not essential to the working of the invention. The method of the present invention can be equally applied where POTS is not available. Moreover, it is to be understood that the method of the present invention applies to all node connection points as defined above in this document and as such includes but is not limited to cross-connect facilities (CCF) such as pillars, cabinets, pits, and main distribution frames (MDF) and could be applied to any copper pair interconnection method or location, which enables FTTx nodes to be connected to exchange and subscriber premises.

The exchange may be any form of exchange including but not limited to a local exchange, a main exchange, trunk exchange, central office (CO), remote exchange or digital loop carrier (DLC). Network Management of services delivered over copper lines from any of these exchange types is typically undertaken by specific management systems such as POTS management systems, DSL management systems or legacy management systems for services such as SHDSL, ISDN or E1/T1 . For simplicity the term "CO management system" will be employed throughout this document to describe any or all of these management systems.

Moreover, it is to be understood that whilst the subscriber may be connected to a local exchange via a cross connect facility, the connection between the FTTx node and the exchange may connect the FTTx node either to the same local exchange or to a main exchange without affecting the operation of the method of the present invention.

In a preferred embodiment, the step of establishing a connection between the FTTx node and the node connection point involves installing a single copper pair for each subscriber. This minimises the material and labour costs involved in deployment of the FTTx node in accordance with the present invention.

The method includes the step of remotely activating the first service and deactivating the second service, or remotely deactivating the first service and activating the second service. That is, when the first service, e.g. POTS and/or DSL is activated from the exchange, the second service, e.g. FTTx POTS and/or FTTx DSL is placed in a deactivated state and vice versa.

In a particularly preferred form of the invention, the first service includes one or more of a narrowband service, a broadband service or a legacy service. Moreover, the second service includes one or both of a narrowband service and/or a broadband service.

In a particular embodiment, wherein the first service includes a broadband service or a legacy service and the second service includes a broadband service, the method further includes the step of minimising interference to a broadband or legacy service provided by the first service from a broadband service provided by the second service by increasing an impedance of a line connection between the FTTx node and the node connection point when the second service is deactivated and decreasing the impedance when the second service is activated.

In one particular implementation of the invention, the narrowband service comprises plain old telephony service (POTS) and the method further includes the step of preventing interference between a POTS service provided by the first service with a POTS service provided by the second service by isolating a POTS circuit from ring voltages generated by the first service when the second service is deactivated.

This may be achieved by configuring a ring generator on the POTS service provided by the second service such that its peak ring voltage is set below an over-voltage protection level installed on the POTS service provide by the first service.

In another form of the invention, the method further includes several steps to optimise utilisation of the FTTx node ports by confirming the FTTx connections are made to all existing subscriber connections carrying an active service by utilising an active line test. This step further minimises the material and labour costs involved in deployment of the FTTx node by ensuring all existing services are ready for migration to the FTTx node before field staff leave the node connection point location thereby avoiding the need for expensive revisits to the same location.

With all active subscriber lines now connected to FTTx node ports at the node connection point, an optional subscriber line identification test may be performed to verify the identity of the subscriber line used by each subscriber and its connectivity to the FTTx node. This test may involve creating a first line connection condition at the exchange and detecting a second line condition at the FTTx node, or creating a first line connection condition at the FTTx node and detecting a second line connection condition at the exchange, wherein if the first and second line connection conditions are the same, correct line connectivity and identification is confirmed. In one particular embodiment, creating the first line connection condition involves placing the line connection in a line test condition. The line test condition may be for example an off-hook condition in the case of a POTS system, or a line looped condition in the case of a DSL system. This line test condition initiated by the FTTx node may be detected as an off-hook condition in the case of a POTS system at the exchange or as an impaired line condition in case of a DSL or legacy system at the exchange.

The subscriber line identification test may include the following steps: (a) communicating with the CO management system to prepare it for the subscriber line identification test; (b) selecting a subscriber line connection between the FTTx node and the exchange for testing; (c) placing the selected line connection in a line test condition; (d) initiating detection of the line test condition by the CO management system.

If the CO management system detects that the selected line is in the line test condition, it communicates the line identification information to the FTTx management system which returns the selected line connection to an idle condition. If the CO management system does not detect that the selected line connection is in the line test condition, this is communicated to the FTTx management system which adds the selected line connection to an exception report.

The idle condition is an on-hook condition in the case of a POTS system, or a normal state in the case of a DSL system.

If there are no pre-configured line identification records in the FTTx management system, then this line identification is recorded in the FTTx management system. If there were pre-configured line identification records in the FTTx management system, but the line identification information does not match those records, then this line and the line identification information is added to a "Line ID Mismatch" exception report. Alternatively, if the CO management system does not detect that the selected line connection is in the line test condition, this result is communicated to the FTTx management system and the FTTx management system adds the selected line connection to a "Lines not Identified" exception report.

In one particular form, the step of initiating the subscriber line identification test involves switching a relay in the FTTx node.

Preferably, the subscriber line identification test is repeated for each line connection between the FTTx node and the exchange before the field staff leave the node connection point location.

The subscriber line identification test results may further be utilised to amend the subscriber records associated with the line configuration information in the FTTx management system with newly obtained line identification information for each subscriber, thereby reconfiguring the FTTx subscriber line records. That is, the method may further include the step of reconfiguring the subscriber records of a line connection by testing one or more line connections between the exchange and the node connection point to detect a line connection in the test condition. If a line connection is detected in the line test condition, the identity of the line connection may be provided to the FTTx management system which may then reconfigure subscriber records associated with the line connection.

According to another aspect of the present invention, there is provided a system for migrating at least one of a plurality of subscribers from a first service to a second service, including:

(a) an exchange involved in provision of the first service;

(b) a FTTx node involved in provision of the second service;

(c) a node connection point;

(d) a first line connection connecting the subscriber to the exchange via the node connection point; and

(e) a second line connection connecting the subscriber to the FTTx node via the node connection point; and

(f) a network management centre for remotely activating the first service at the exchange and deactivating the second service at the FTTx node, or remotely deactivating the first service at the exchange and activating the second service at the FTTx node;

wherein the subscriber remains physically and simultaneously connected to both the FTTx node and the exchange at all times.

The second line connection may include a single copper pair for each subscriber between the FTTx node and the node connection point.

By enabling the subscriber to remain physically connected to the exchange at all times during installation of the FTTx node, interruption to existing exchange based services during this installation is significantly reduced or eliminated. This is a significant improvement over alternative "flash-cut" or "relay-based" installation procedures.

Preferably, the network management system includes a CO management system for managing connection of the subscriber to the first service and a FTTx management system for managing connection of the subscriber to the second service.

The first service may include one or more of a POTS service or a DSL service or a legacy service and the second service may include one or both of a POTS service or a DSL service.

The FTTx node may further include a relay switch for initiating a subscriber line identification test to verify the connection between the subscriber and the FTTx node.

According to one embodiment, connecting a subscriber line includes detecting if a line at the FTTx node has an active service by performing a line test such as looping the line.

Alternately, connecting a subscriber line includes detecting if a line at the FTTx node has an active service by detecting the presence of a DC voltage using an enhanced metallic line testing ("MELT") function.

In a particular embodiment, connecting a subscriber line includes the following steps: (a) connecting one or more FTTx node ports to one or more active subscriber lines if line cross connect records are reliable; or (b) connecting all subscriber lines to an FTTx node port, where the number of FTTx node ports exceeds the number of available subscriber lines; or (c) connecting FTTx node ports to subscriber lines having an existing jumper connection to the exchange; and (d) moving any FTTx node ports connected to non-active subscriber lines, to untested subscriber lines with a jumper; and

(e) repeating steps (a) to (d) until all subscriber lines with an existing jumper have been tested.

The method may further include the step of performing an active line test on all lines connected to FTTx node ports to determine whether each line connection has an existing service.

If a selected line connection is detected as not having an existing service, the selected line connection may be added to an exception report.

In a particular form of the invention, the step of performing the active line test involves switching a relay in the FTTx node.

According to another aspect of the present invention, there is provided a method for migrating at least one of a plurality of subscribers from a first service connecting the subscriber to an exchange to a second service connecting the subscriber to a FTTx node, the subscriber being connected to the first service via a subscriber line, the method including the following steps:

(a) establishing a connection between the FTTx node and the subscriber line at a node connection point located on the subscriber line between the exchange and the subscriber via a controllable impedance arrangement; and

(b) remotely activating the first service at the exchange and deactivating the second service at the FTTx node and increasing an impedance of the connection between the FTTx node and the node connection point to minimise interference between a broadband or legacy service provided by the first service with a broadband service provided by the second service; or

(c) remotely deactivating the first service at the exchange and activating the second service at the FTTx node and decreasing the impedance of the connection between the FTTx node and the node connection point when the second service is activated;

wherein the subscriber remains physically and simultaneously connected to both the exchange and the FTTx node via the controllable impedance arrangement. The impedance of the connection between the FTTx node and the node connection point may be controlled by an FTTx node signal on the line to be migrated. In some particular embodiment, the impedance is controlled by a MELT function.

It should be noted that any one of the aspects mentioned above may include any of the features of any of the other aspects mentioned above and may include any of the features of any of the embodiments described below as appropriate. Brief Description of the Drawings

Embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings. It is to be understood that the particularity of the drawings does not supersede the generality of the preceding description of the invention.

Figure 1 is a schematic diagram showing a typical configuration of combined digital subscriber line (DSL) and plain old telephony service (POTS) delivery.

Figure 2 is a simplified schematic diagram showing a configuration of combined digital subscriber line (DSL) and plain old telephony service (POTS) delivery via a FTTx node in accordance with an embodiment of the present invention.

Figure 3 is a more detailed schematic diagram showing the configuration of combined digital subscriber line (DSL) and plain old telephony service (POTS) delivery via a FTTx node shown in Figure 2.

Figure 4 is a flow chart showing an overview of the method of migrating a subscriber from a first service provided via the exchange to a second service provided via the FTTx node according to an embodiment of the present invention.

Figure 5A is a flow chart showing the subscriber line connection process.

Figure 5B is a schematic diagram showing the typical services and connections at the node connection point for exchange and subscriber lines Figure 6A is a flow chart showing the method of conducting an optional subscriber line identification test and reconfiguration of subscriber line records in accordance with an embodiment of the present invention.

Figure 6B is a system diagram showing subscriber line identification test options for typical network configurations

Figure 7A is a schematic diagram providing a functional overview of the xDSL line driver.

Figure 7B is a schematic diagram showing a typical implementation of the xDSL line driver.

Figure 7C is a schematic diagram showing a functional overview of a high impedance circuit implementation external to the DSLAM

Figure 8A is a schematic diagram providing a functional overview of the POTS line driver.

Figure 8B is a schematic diagram showing a typical implementation of the POTS line driver.

Figure 9A is a schematic diagram providing a functional overview of the subscriber line identification test for FTTx POTS.

Figure 9B is a schematic diagram showing a typical implementation of the subscriber line identification test.

Figure 9C is a schematic diagram providing a functional overview of the subscriber line identification test for FTTx DSL.

Detailed Description

The term node connection point ("NCP") refers to the copper line connection point at which the newly installed FTTx node connects to the existing copper line connecting the exchange and the subscriber. The node connection point is typically located at an existing cross connect point which includes but is not limited to cross-connect facilities (CCF) in a street-side cabinet or "pillar" or connections made in a pit or manhole or main distribution frame (MDF) or customer's premises. Alternatively, the node connection point may be at locations where there is no existing CCF, hence requiring new connect points to be established by making new line junctions between the FTTx node equipment and the exchange to subscriber line whether made by "triple termination" formed by bridging the FTTx node copper line to the existing line or by "break and make" of the copper line during node installation.

Referring firstly to Figure 2 there is shown an example configuration of combined digital subscriber line (DSL) and plain old telephony service (POTS) delivery via a FTTx node. POTS 4 are delivered from a local exchange 1 via a low pass filter 5 and interconnected with DSL services delivered from a digital subscriber line access multiplexer (DSLAM) 2 via a high pass filter 3. The line connection from the exchange 6 connects to subscriber premises 12 via a CCF 10 which is typically located in a street-side cabinet or "pillar".

The line connection from the local exchange 6 and the line connection from the subscriber premises 1 1 both terminate at the CCF 10 on termination blocks 7a & 7b respectively. A jumper line 8 interconnects the termination blocks 7a & 7b to complete the connection between the exchange 1 and the subscriber premises 12. At the subscriber premises 12, the subscriber line 1 1 connects to a DSL modem 14 via a high pass filter 13 and telephony equipment or POTS 16 via a low pass filter 15.

In accordance with the present invention, the configuration includes simultaneous connection of the FTTx node 18 and the exchange 1 to the subscriber premises 12. This is achieved by interconnecting the FTTx node 18 to the subscriber line 1 1 . In Case A where a CCF is co-located with the FTTx node installation, this interconnection is made at a terminal block 7b thereby establishing the node connection point 9a via a copper pair 17a. In Case B, where there is no co-located CCF with the FTTx node installation, a new node connection point 9b is created on the subscriber line 1 1 by making a new connection between copper pair 17b and subscriber line 1 1 .

From the node connection point, the copper pair 17a or 17b connects at the FTTx node 18 to a DSL port 19 in the DSLAM via a high pass filter 20 and optionally POTS port 21 via a low pass filter 22. The FTTx node 18 is connected to the local exchange 1 or alternatively a main exchange (not shown) via optical fibre connection 23. Note that the FTTx node 18 may not include POTS 21 and the associated LPF 22 if the exchange POTS service is to be transferred to a VoIP or similar service using the broadband link from the FTTx node. Referring now to Figure 3, once the subscriber is simultaneously connected to the exchange 1 and the FTTx node 18, POTS can be activated or deactivated either from the exchange using the CO management system 28 or the FTTx node using the FTTx management system 29. The Network Management Centre 27 controls the operation of all services from both the exchange and the FTTx node. The Network Management Centre utilises both the CO management system 28 connected to the exchange via path 31 and the FTTx management system 29 connected to the FTTx node via path 26. When POTS is activated from the exchange 1 , the FTTx POTS 21 is placed in a deactivated state. Vice versa, when POTS is activated from the FTTx node 18, the exchange POTS 4 is placed in a deactivated state. The deactivated state on the FTTx POTS 21 is configured to mimic the characteristics of a short copper pair stub, thereby having minimal impact on POTS performance.

The over-voltage protection on the FTTx POTS 21 is configured to accept typical ring voltages from the exchange 1 when in the deactivated state. The ring generator on the FTTx POTS 21 is further configured to allow the peak ring voltage to be set below the over-voltage protection on the exchange POTS 4. Further detail regarding the POTS line driver circuit is provided in Figures 8A & 8B.

Similarly, DSL services can be activated from either the exchange 1 or

FTTx node 18 using either CO management system 28 or FTTx management system 29 respectively. When the DSL service is activated from the exchange 1 , the FTTx DSL service 19 is placed in a deactivated state. Vice versa, when the DSL service is activated from the FTTx node 18, the exchange DSL service 2 is placed in a deactivated state. The activated and deactivated states are controlled by the CO and FTTx management systems 28 & 29 respectively. The deactivated state on the FTTx DSL service 19 is configured to mimic the characteristics of a short copper pair stub, thereby having minimal impact on DSL service performance.

In a similar fashion, legacy services (e.g. SHDSL, ISDN or E1/T1 ) can be activated or deactivated from the exchange 1 , and replaced with DSL services from the FTTx node 18 using the CO management system 28 and FTTx management system 29. Referring now to Figure 4, the FTTx node is connected at the node connection point to all required subscriber premises at 32. The FTTx node may contain DSL and POTS or DSL only technology. In order to confirm the identity of each connected subscriber line, it may be decided at 33 to perform an optional automated subscriber line identification test at 34 between the exchange and the FTTx node. The subscriber line identification test is typically useful where some lines now connected to the FTTx node were previously not uniquely identified at the time of connection. If lines cannot be automatically identified at 35, these are recorded as "Lines not Identified" at 37 and will undergo manual troubleshooting or identification at 38. Lines which are correctly identified at 35 can then undergo remote service migration and activation as required at 36 to the relevant FTTx services at 39 or 40. Note that exchange-based POTS may be migrated to node-based POTS at 39 or alternatively migrated to node-based DSL at 40 and carried within the broadband DSL stream as VoIP or another voice service encapsulation. Legacy services may also be migrated to new node-based DSL services at 40.

Referring back to Figure 3 the subscriber line identification test described in detail with reference to Figure 6A establishes correct connectivity and identification of the line 17a or 17b for Case A and Case B respectively at the FTTx node 18. The POTS ports 21 & DSL ports 19 are also uniquely mapped to each subscriber line for the significant numbers of subscribers that are typically connected to individual copper pairs 1 1 at the node connection point 9a or 9b. Once the connectivity and identification of each copper pair has been verified by the subscriber line identification test, field staff are no longer required at the node connection point location, thereby reducing the time for which field staff are required on location thereby reducing the cost of FTTx node deployment. Each subscriber's individual service can then be remotely activated or switched between the exchange and the FTTx node.

In a typical embodiment of the present invention, for cases where POTS is to be installed at the FTTx node, the subscriber line identification test involves utilisation of the relay switch 24a and line test function 25 in the FTTx node 18. For cases where only DSL is to be installed at the FTTx node, the line identification test involves utilisation of the relay switch 24b and line test function 25 in the FTTx node 18. Moreover, the subscriber line identification test requires interconnection 30 of the CO management systems 28 with the FTTx management system 29 to enable message state information to be communicated between the two systems.

Referring now to Figure 5A, the line connection process undergoes several steps to optimise utilisation of FTTx node ports when connecting them to subscriber lines. For service continuity and to minimise operational costs, all active subscriber lines should be connected to an FTTx node port to enable the future remote migration of services from the exchange to the FTTx node. Furthermore and where possible, non-active subscriber lines should also be connected to an FTTx node port to support remote service activation, thereby lowering costs by eliminating the future need for individual manual connection of services to the subscriber line.

If line cross-connect data is reliable at 41 then these records can be used to identify active subscriber lines for connection to FTTx node ports at 42. Alternatively if there are sufficient FTTx node ports at 43 to connect to all subscriber lines, then all subscriber lines should be connected at 44 to a FTTx node port. If there are insufficient FTTx node ports to connect to all subscriber lines, then subscriber lines with existing jumpers to the exchange should be connected at 45. These steps are to identify all active lines and ensure they are connected to a FTTx port (initially only some of the lines with jumpers will be connected). See Figure 5B for an explanation of the typical exchange and subscriber line connections and services.

Although most subscriber lines with existing jumpers have active services, some may not have active services. A decision may be taken at 46 to perform an optional active line test at 48 to confirm which lines have active services. One embodiment of the active line test may include detection of a service by use of the subscriber line test options detailed in Figure 6B. Another embodiment may use an enhancement of a MELT function to detect the presence of a DC voltage on the subscriber line thereby confirming the presence of an active POTS or other service on that line.

A FTTx node port found to not have active services after connection to a subscriber line can be moved to the next subscriber line with a jumper at the node connection point and which has not yet been connected to an FTTx node port and the active line test repeated. If the line is found to not to have an active service 51 , the line is added to an exception report "Non-Active Lines" 50. If the line is found to have active services at 50, the system then checks if all lines currently connected to FTTx ports have been tested at 52, and if not it repeats the test for the next connected line at 53. Once all lines currently connected to the FTTx node have been tested, a check 54 is made if there are other lines with jumpers which have not yet undergone the active line test. In order to optimise the utilisation of the FTTx ports, any FTTx ports connected to lines previously identified as "Non-Active Lines" will not be utilised. Therefore, these ports may be re-allocated to other subscriber lines with jumpers which have not yet been tested 55. The active line test process may continue until all lines have been tested to identify all active and non-active subscriber lines as well as lines which cannot be identified "Lines not Identified" 47 and which must then undergo a subsequent manual test procedure 49 if identification is required. At completion of this line connection process, the optional subscriber line identification test 56, described in Figure 6A, may be undertaken. This completes at 57 the subscriber line connection process.

Referring now to Figure 5B, this schematic provides an outline of the typical exchange and subscriber line connections and services which may be found at the node connection point. In Case A where an existing CCF is available for connection, the exchange lines 60 connect to the subscriber lines 62 via jumpers 61 at the CCF 58. Connections to the FTTx node 63 are made to the CCF 58 at the node connection point 59. In Case B where there is no existing CCF, connections to the FTTx node 66 are made directly to the subscriber lines 65 at the node connection point 64.

As an example only, Figure 5B illustrates exchange lines which may be active and carrying a range of services including POTS, DSL or legacy services. Additional exchange lines are also shown which are non-active lines as they are vacant or carry disconnected services.

With regard to connections at the node connection point, the following must also be noted:

(1 ) When performing the optional subscriber line identification test: i. Non-active lines cannot be identified - hence these must be included in the exception report "Non-Active Lines" at 50 ii. Some active lines may not be identified - these must be included in the exception report "Lines not Identified" at 47 & at 76.

(2) The number of subscriber lines may be > number of exchange lines;

(3) Not all lines with jumpers are active as some previous services may have been disconnected but Jumper left in-situ;

(4) For continuity of existing services, the number of FTTx ports must be≥ the number of active lines.

Referring now to Figure 6A, the optional subscriber line identification test and subscriber record reconfiguration process is described in more detail starting at 67. The FTTx management system selects a line connection to test 68 and communicates these details to the CO management system 69. The FTTx management system initiates the subscriber line test function for the line to be tested using the relevant approach described in Figure 6B. The selected line connection on the FTTx node is placed into the line test condition at 72.

Figure 6B outlines subscriber line identification test options for two typical network configurations. Alternate configurations may also be deployed which similarly utilise the techniques described herein. In Case 1 , both POTS and DSL 96 are to be deployed at the FTTx node 94, and in Case 2, only DSL 97 is to be deployed at the FTTx node 94. Existing services from the exchange 93 to be migrated to the FTTx node may include POTS/DSL (a) or DSL only (b) or legacy (c).

In a typical embodiment of this configuration, the subscriber line identification test functionality is part of the equipment at the FTTx node 94. In a typical embodiment, the subscriber line identification test may incorporate any or all of the functionality provided by Metallic Line Testing ("MELT"), or Single-Ended Line Testing ("SELT"), or Dual-Ended Line Testing ("DELT"), or other proprietary functionality which tests the status and performance of the copper pair from the test initiation point 96 & 97 to the customer premises 95. In another embodiment, a simple subscriber line test implementation may incorporate only a line looping function or it may incorporate a line looping function in addition to any or all of MELT, SELT or DELT. A variety of test methods are hence typically available using this subscriber line identification test functionality from the FTTx node.

In both Case 1 and Case 2, a FTTx node based subscriber line identification test is initiated by looping a specific line under control of the FTTx Management System. The correct line connection at the FTTx node is typically confirmed by one of the following methods: (1 ) POTS at exchange (a) detects an off-hook condition for that specific line; or (2) if only DSL (b) or legacy system (c) at exchange, the CO management system detects a line impaired condition (e.g. reduced SNR margin) for that specific line.

After the FTTx management system controls the subscriber line identification test functionality at the FTTx node to initiate a subscriber line test on a specific line, the POTS equipment at the exchange can detect the off- hook condition for that specific line. Alternatively for lines which do not have a POTS service, the DSL or legacy equipment at the exchange will detect a degraded or impaired condition for that specific line. Initiating a test by creating a line loop is one embodiment of this invention to undertake subscriber line identification testing.

Depending on the type of equipment at the exchange, the type of impairment on the specific subscriber line under test may be detected by a reduction in SNR margin or line error detection or monitoring of line re- synchronisation or by other alternative line status monitoring techniques.

Referring back to Figure 6A, the FTTx management system avoids testing line connections already in a line test condition at 70 and records these lines in a "Delay Test List" at 71 . After a pre-determined time at 86, the FTTx Management system may retest a line connection which had previously been added to the "Delay Test List" at 71 , before signalling the CO management system to test another line at 68. To test if the line is in a line test condition (e.g. an off-hook condition), the MELT functionality in the FTTx node may be used to measure the DC voltage across the line. If the measured DC voltage is the nominal open circuit POTS feeding voltage (typically 48VDC), the line is not in use (i.e. POTS is on-hook). However, if the measured DC voltage is significantly lower than the nominal feeding voltage then the line has been looped and is in use (i.e. POTS is off-hook). After a line connection is successfully placed into the line test condition at 72, the FTTx management system sends an acknowledgement to the CO management system at 73 indicating that the line connection is in the line test condition (e.g. off-hook condition). This acknowledgement initiates line detection by the CO management system.

If the POTS management system detects an off-hook condition at 74 or if the DSL/legacy management system detects an impaired condition at 75 as described with reference to Figure 6B, the relevant management system records the line identification (ID) at 77 and reports this tested line ID information to the FTTx management system at 78. In the significant majority of cases, this test will result in a single unique subscriber line being identified. It should be noted, however, that if other subscriber lines are looped by their subscribers at the same time as the line identification test is activated at 72, then two or more lines may be identified by the CO management system. In this scenario, the subscriber line under test should be added to the "Lines not Identified" exception report at 76.

In the usual case where there is a single unique subscriber line identification at 74 or at 75, the FTTx management system checks this tested line ID information against its existing recorded information at 79. If the FTTx management system was not pre-configured with line ID information at 80 then it stores this tested line ID information as the new subscriber record for the line under test at 81 . Alternatively if the tested line ID information did not match the pre-configured FTTx line ID records at 82, then this line is added to a "Line ID Mismatch" exception report at 83. If the Subscriber Line Test Option was not successful at 75, then this line is added to the "Lines not Identified" exception report at 76.

The FTTx management system then returns the line connection to the idle condition at 84. The line identification test procedure then cycles to the next line connection to be tested at 85. After all lines have been cycled through, any lines previously deferred and registered on the "Delay Test List" are then tested at 86.

Once all lines have been tested, each line in the "Line ID Mismatch" exception report can be analysed at 87. If subscriber line records are to be reconfigured at 88, the tested Line ID information obtained during the testing procedure can be recorded in the FTTx management system thereby reconfiguring the subscriber line records at 91 or alternatively added to the "Lines Not Identified" exception report at 89. All lines on the "Lines not Identified" exception report at 89 may undergo a manual procedure to identify the line at 90 before ending the overall subscriber line identification test at 92.

Accordingly, the subscriber line record reconfiguration procedure potentially further reduces node installation costs by rapidly resolving failed connections or line identification which would otherwise require manual re- work on-site.

In some cases system modifications may be required to support the method of the present invention as described with reference to Figures 7A through to 9C.

Referring firstly to Figures 7A & 7B, the FTTx node is connected at the node connection point 100 to the subscriber line from the exchange 98 and the subscriber line to the customer 99 which is carrying the existing POTS and DSL services. The line impedance of the xDSL line driver circuit 102 is engineered to minimise any degradation to existing DSL service performance when the FTTx node DSL is in the deactivated state, i.e. prior to service cut- over. When the xDSL line driver circuit is activated via the control device 103, the xDSL line driver circuit is returned to its nominal configuration.

Loading on the line connection 101 is minimised by adding a suitable resistor 104 in series with the DC blocking capacitor 105 which is connected between the primary windings of the xDSL line transformer 106. This enables the existing DSL service to continue operating to the subscriber with little or no degradation of the service due to the new FTTx connection.

When the FTTx DSL takes over from the Exchange DSL operating to the subscriber, the resistor 104 is shorted out by the control device 103, which in this embodiment example comprises an opto-coupled MOS relay 107. The MOS relay is activated by activation of the FTTx DSL service.

In an alternate embodiment, a controllable high impedance circuit external to the DSLAM is used to minimise loading of the line connection. Referring to Figure 7C, loading of the line connection 101 is minimised by using a controllable high impedance circuit 102a in which relay contacts 102c disconnect the subscriber line 100 from the DSLAM line driver circuit 103b. This configuration enables the high impedance circuit to be at a different physical location to the DSLAM and typically closer to the node connection point.

In order to activate the FTTx DSL service and take over from the exchange DSL operating to the subscriber, a control signal 103a is sent to the MELT circuit 103c which generates an AC or DC voltage or suitable trigger to activate relay 102b. When activated, relay 102b connects the subscriber line 100 to the DSLAM line driver 103b via the line connection 101 . In one embodiment, relay 102b may be a latching relay so that once activated it remains in that state, therefore permanently connecting the DSLAM to the subscriber line. This enables the existing DSL service to continue operating to the subscriber with little or no degradation of the service due to the new FTTx connection. Utilising the DSLAM MELT function also has the advantage of implementing this migration method without requiring changes to an existing DSLAM product.

In other embodiments, other electronic devices such as solid state devices may be used to provide this high impedance circuit as an alternative to the latching relay described herein.

For deployments which require POTS in addition to DSL services at the FTTx node location, refer to Figures 8A & 8B. The FTTx POTS circuit incorporates a line disconnect feature 108 on all line connections to isolate the POTS protection circuit 109 from exchange generated ring voltages until such time that migration occurs. The POTS protection circuit 109 is therefore not subjected to ring voltages from the exchange whilst FTTx POTS is in the deactivated state.

The ring generator 110 on FTTx POTS is designed to enable its peak ring voltage to be set below the over-voltage protection levels installed on the exchange POTS.

A line disconnect relay 1 1 1 which is a standard part of the POTS circuit 1 15 (see Figure 9A) is used to isolate the POTS protection circuit 1 12 and prevent FTTx POTS from interfering with POTS originating from exchange. After migration occurs the POTS protection circuit 1 12 will assume the role of the equivalent circuit at the exchange.

Referring finally to Figures 9A, 9B & 9C after installation and connection of FTTx node at the node connection point, in one embodiment of the present invention a line loop facility may be used to test line connectivity and identification. A line loop connected across the common test bus 1 18 can be switched to each subscriber line in turn by a line test relay 1 14 under the direction of the FTTx management system. This allows each line via the test relay 1 14 to be switched to the line loop 1 13 in turn. Figure 9B provides more detail of this implementation with the line test relay 1 16 used to switch the line to a suitable resistor 1 17 which loops the line. Detection of an off-hook condition on the correct line at the exchange indicates correct connection of the copper pairs at the node connection point and that a good connection exists.

Referring to Figure 9C, for deployments where only DSL is installed at the FTTx node, the same method of the present invention is employed to test connectivity of each line of the DSL Circuit 121 by using a line loop 1 19 switched via line test relay 120 and test bus 122.

Careful consideration is required to be given to system design to minimise any adverse impacts on performance when the FTTx node and exchange equipment are simultaneously connected to the subscriber. It is the role of the CO and FTTx management systems to ensure that similar services, i.e. exchange DSL and FTTx DSL are not simultaneously active.

Moreover, to minimise adverse impacts on performance, the method of the present invention should be deployed within engineered minimum and maximum line lengths between the FTTx node, the exchange and the subscriber premises. For example, in order to minimise performance impairment these engineering limits will restrict use of the method of the present invention in close proximity to the exchange.

One of the main advantages of the existing relay-based node installation approach is that it can switch out undesirable shunt impedances which would otherwise impair the transmission path of the DSL service selected by the subscriber (whether exchange DSL or FTTx DSL). This ensures that line connection losses are minimized and that optimum transmission capacities are attained.

Without such a relay matrix, a significant impairment occurs to xDSL when the subscriber selects the exchange-based DSL option, which is typically provided via an ADSL or ADSL2+ system. If the line connection between the FTTx node and the subscriber premises is relatively short, as will often be the case, both downstream and upstream transmission rates can fall in excess of 60% when compared with corresponding relay-based capacities. This significant degradation of performance results from shunting of the line connection by an effective low input impedance presented by the idle FTTx DSL circuit.

Since the method of the present invention causes the idle FTTx DSL transceiver input impedance to stay high for all possible line connection lengths between FTTx node and subscriber premises, the detrimental shunting effect is greatly reduced. Laboratory measurements and system modelling has shown that the method of the present invention enables ADSL or ADSL2+ transmission capacities to remain typically within approximately 95% of those that would be obtained with a relay-based approach. In the worst case scenario, i.e. the longest ADSL/ADSL2+ line lengths, the capacities remain within 90% of the corresponding relay-based values. This very large capacity improvement over the worst case scenario that otherwise apply without a relay matrix is a significant advantage of the migration method of the present invention.

When a subscriber selects an FTTx DSL service option, the transceiver input impedance at the FTTx node is returned to its nominal configuration. However, since the unused section of line connecting the FTTx node back to the exchange remains connected, it mimics a typical long stub and shunts the DSL signal path. Consequently this long stub somewhat impairs the transmission capacity of the FTTx DSL system.

In considering a particular exemplary implementation of the method of the present invention using VDSL, the VDSL2 systems incorporate upstream power back-off (UPBO) and the stub has different impacts on each direction of transmission. For normal VDSL2 provisioning (i.e. line lengths inside the UPBO range of up to 800metres) and assuming that all VDSL2 services from the same FTTx node have similar shunting stubs (which is normal for most node locations) the upstream capacities typically remain within approximately 70-90% of capacities that would be obtained with the relay matrix approach. Under the same deployment conditions, but for line lengths less than the typical UPBO range, the downstream capacities remain within approximately 90-95% of capacities that would be obtained with the relay matrix approach.

Once all exchange services have been migrated to the FTTx node, the subscriber line between the node connection point and the exchange may be disconnected at the node connection point, thereby resulting in the subscriber line being connected directly and solely to the FTTx node. This removes the shunting stub described above and the consequential performance impacts, thereby removing any degradation resulting in 100% VDSL2 performance.

The method of the present invention enables the FTTx node to be located and connected at any point on the subscriber line by appropriate selection of the node connection point location. This provides the significant benefit of enabling flexibility when determining the location of the FTTx node. For DSL systems the bandwidth achievable to the subscriber increases as the distance between the FTTx node and the subscriber decreases. Therefore the location of a FTTx node should be located as close as possible to the subscriber. Hence the ability to flexibly determine the location of the FTTx node using the method of the present invention enables the potential bandwidth for subscribers to be optimal and maximised.

Moreover, the method of the invention advantageously provides a means for connecting a FTTx node to existing subscriber lines with no or minimal interruption to existing exchange services, and ready for the subsequent migration of at least one of a plurality of subscribers from a first service to a second service. Furthermore, the existing exchange broadband service can be migrated to the FTTx node independently and therefore at a different point in time to the migration of the existing exchange narrowband service to the node

Addition of the subscriber line connection process ensures correct connection of FTTx ports to active subscriber lines. It is to be understood that various alterations, additions and/or modifications may be made to the parts previously described without departing from the ambit of the present invention.

The present application may be used as a basis or priority in respect of one or more future applications and the claims of any such future application may be directed to any one feature or combination of features that are described in the present application. Any such future application may include one or more of the following claims, which are given by way of example and are non-limiting in regard to what may be claimed in any future application.