MELT with reverse power feed

Abstract

This document discloses a network node and an apparatus that can be deployed in a network system for MELT with reverse power feeding. The network node can be coupled to the apparatus via a transmission line. In particular, the network node may include a module for: receiving power from the apparatus via the transmission line; performing line measurements on the transmission line; and signaling the apparatus to be disconnected from the transmission line, wherein the module may be further configured to perform line measurements on the transmission line during a time period when the apparatus is disconnected from the transmission line. The apparatus may include a module for: providing power to the network node; monitoring at least one electrical parameter of the transmission line; and disconnecting the apparatus from the transmission line if a predetermined line condition or power violation is detected, so that the network node can perform measurements on the transmission line.

Description

Technical Field

[0001] The present disclosure relates generally to measurements in network systems. In particular, the present disclosure relates to power management for facilitating measurements in network systems where reverse powering is deployed. Background Art

[0002] Generally speaking, Digital Subscriber Line, hereinafter abbreviated as DSL in this document, is a family of broadband high-speed technologies for transmitting digital data over, for example, twisted pair or copper wires, such as asymmetric DSL (ADSL), very high bit rate DSL (VDSL) and the like.

[0003] Typically, in such xDSL network systems, a metal line test (hereinafter abbreviated as MELT in this document) as defined in ITU-T G.996.2 is a test mechanism for testing twisted pairs. It is typically used to monitor the quality of twisted pairs and debug field problems. The circuits that perform these measurements are typically integrated on the operator side of the twisted pair loop, for example in a distribution point unit (hereinafter abbreviated as DPU in this document). Typically, the mechanism relies on measuring external DC and AC voltages, resistances and / or capacitances between the positive line (Tip) and the negative line, the negative line to ground and / or the positive line to ground. In order to perform resistance and / or capacitance measurements, a test voltage in a frequency range from DC to 4kHz can be set between the positive line and the negative line or between the positive line / negative line and ground through a relatively high impedance so that the resulting current can be measured.

[0004] On the other hand, technologies like Reverse Power Feed (abbreviated as RPF hereinafter in this document) have been developed to power the DPU from the customer or user equipment by injecting power onto the corresponding user / DSL line in addition to the data-carrying signals. However, the RPF may typically introduce a voltage source of about 60V (sometimes also referred to as power source equipment, abbreviated as PSE hereinafter in this document), which is connected to the line through a power splitter (abbreviated as PS hereinafter in this document). Similarly, on the DPU side, a power extractor (abbreviated as PE hereinafter in this document) is also connected to the line through the PS. This voltage source typically provides a low output impedance between the positive and negative wires on the line, which is required to provide DC power to the DPU through the twisted pair. It is worth noting that this voltage source may prevent the DPU from performing the MELT test. Summary of the invention

[0005] In view of some or all of the above-mentioned problems and / or use cases, the present disclosure generally proposes a management mechanism that can be used in network nodes (e.g., distribution point units) and / or terminals or customer equipment / devices (e.g., power supply units of end-user customer equipment) deployed in a communication network (e.g., a network based on xDSL technology).

[0006] As a broad aspect, a network node that can be deployed in a network system (e.g., a network system based on xDSL) is provided. For example, the network node can be a DPU or form a part of a DPU. In particular, the network node can be coupled (or coupled) to a device via a transmission line. As an example and not limitation, the device can be an end-user terminal device typically located at a customer equipment or form a part thereof. The transmission line can be an xDSL subscriber line (e.g., a twisted pair).

[0007] In particular, the network node may include modules for:

[0008] - receiving power from the device via a transmission line;

[0009] - perform line measurements on the transmission line; and

[0010] - signalling the device to disconnect from the transmission line,

[0011] Wherein the module is further configured to perform line measurements on the transmission line during a time period when the device is disconnected from the transmission line.

[0012] In an embodiment, as will be appreciated by those skilled in the art, power may be provided using reverse power feeding or any other suitable means. The line measurement may be MELT as described above, or any other suitable test / measurement (or in some cases, any other suitable operation). Signaling may occur via a transmission line to a device using, for example, a predetermined signal, such that upon detection of the predetermined signal the device may be configured to disconnect from the transmission line.

[0013] In one embodiment, the module is configured to:

[0014] Applying an invalid or missing predefined signature to the transmission line; or

[0015] A power constraint for drawing power provided from the device is violated.

[0016] In another embodiment, the module is further configured to apply the invalid or absent predefined signature before or during a startup phase of receiving power from the device.

[0017] In particular, in some cases, the invalid or missing predefined characteristic may be applied to the transmission line in response to the apparatus applying a predefined voltage to the transmission line.

[0018] In some cases, the predefined feature may be, for example, a detection feature or a classification feature. As will be appreciated by those skilled in the art, the detection and / or classification feature may be represented in the form of a predefined resistance (or capacitance) feature or a predefined range of allowed voltage and / or current.

[0019] In another embodiment, the module is further configured to perform the violation of the power constraint by drawing a current from the transmission line below or above a predefined limit, and wherein the violation of the power is performed during an operation phase of the node and receiving power from the device.

[0020] The module may be further configured to detect disconnection of the device from the transmission line by monitoring a quantity indicative of a voltage on the transmission line.

[0021] In another embodiment, the module is further configured to signal the disconnected device via the transmission line to reconnect the device back to the transmission line.

[0022] In another embodiment, the module is further configured to signal the device to reconnect back to the transmission line by applying at least one of an AC signal or a predetermined DC voltage to the transmission line.

[0023] Optionally, as will be appreciated by those skilled in the art, the network node may further include a module (eg, a communication unit) for facilitating communication (eg, data signaling, etc.) between the network node and the device through a transmission line.

[0024] So configured, line measurements (eg, MELT) can be successfully performed by a network node (eg, DPU) on a transmission line in an efficient, flexible, and accurate manner, without being affected (or even prevented) by the power provided by the device.

[0025] The module of the network node may be further configured to apply an invalid impedance, current or voltage; or in some cases not even apply any impedance, current or voltage to the transmission line. In one embodiment, the module of the network node may be configured to violate a predefined power constraint, for example, by drawing an invalid power supply provided by the device from the transmission line. For example, if the power constraint is defined as a minimum value / limit (e.g., maintaining a power signature current), then violating such a power constraint may be drawing no current or a current less than the minimum value / limit (e.g., maintaining a power signature current). In contrast, if the power constraint is defined as a maximum value / limit (e.g., continuous output power), then violating such a power constraint may be drawing an excess current higher than allowed according to the maximum value / limit (e.g., maintaining a power signature current).

[0026] So configured, invalid (or missing) predefined features and / or violations of power constraints applied to the transmission line by a network node may be easily monitored and detected by the device coupled on the other side of the transmission line.

[0027] In some examples, before normal operation (or referred to as operation phase) of data exchange and power supply, the network node and the device may need to go through a certain startup process (or referred to as startup phase), for example, to ensure the operability and / or compatibility of the elements of the network system, especially between the network node side and the device (e.g., included in the end-user terminal), so as to successfully enter the operation phase for exchanging data and / or power. That is, during the startup phase, no power is yet provided from the device to the network node. For example, the startup process can be a startup protocol based on metal detection (abbreviated as MDSU hereinafter in this document).

[0028] On the other hand, in some cases, the module may be further configured to perform a violation of the power constraint during an operation phase in which power is received from the device.

[0029] In some examples, the modules of the network node may be further configured to detect (and possibly confirm) disconnection of the device from the transmission line. For example, detection of the disconnection may be achieved by monitoring a quantity indicative of a voltage on the transmission line. As will be appreciated by those skilled in the art, the quantity indicative of a line voltage on the transmission line may be the line voltage itself, a portion or fraction thereof, a current, a resistance, etc. Optionally, (the relevant modules) of the network node may be further configured to discharge any residual supply voltage on the line before line measurements are to be performed.

[0030] In some examples, the device may be configured to reconnect itself after being disconnected for a predefined time period (eg, 20 seconds). The predefined time period may be long enough for completing a line measurement or in some cases a set of line measurements / line measurement sets performed by a network node.

[0031] In some examples, the module of the network node may be further configured to signal the disconnected device via the transmission line to reconnect the device back to the transmission line. The signaling for reconnecting the device back to the transmission line may be actively sent by the network node before the expiration of a predefined time period (e.g., 20 seconds), i.e., before the device reconnects itself. In particular, in some cases, the predefined time period may be relatively long (or even too long) for the network node without power provided from the device in the case of measurement / testing. Therefore, the process of signaling to reconnect the device back to the transmission line (particularly before the expiration of the predefined time period) may be considered useful or beneficial in certain scenarios.

[0032] In some examples, in order to signal to reconnect the device back to the transmission line, the module can be further configured to apply at least one of an AC signal or a predetermined DC voltage (e.g., 50 or 60V) to the transmission line. In particular, the AC signal can be considered to indicate a power level supported by the network node. The power level can be defined, for example, in the form of a maximum power supported, a DC voltage, a line current, or a combination thereof, or as will be understood by those skilled in the art, can be defined in any other suitable manner. An example of a possible definition of a power level (but not limited to this) can be the RPF levels SR1, SR2, and SR3 specified in ETSI TS101 548-1. Similarly, the DC voltage can be predetermined to be high enough (e.g., 50 or 60V), for example, to be able to indicate that there is no off-hook phone. As will be understood by those skilled in the art, the signaling generation and transmission process can be implemented by any appropriate circuit (e.g., in some cases, to reuse the circuit to perform line measurement). For example, the AC signal may be represented in the form of a frequency shift keying (hereinafter abbreviated as FSK in this document) or amplitude modulation (hereinafter abbreviated as AM in this document) signal, with a sine wave frequency in the range of 1 kHz to 2.5 kHz. Of course, other suitable signals (e.g., different formats and / or combinations) may be used or defined to enable the device to be reconnected back to the transmission line.

[0033] In some examples, the modules of the network node may include at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the network node to at least perform:

[0034] - receiving power from the device via a transmission line;

[0035] - perform line measurements on the transmission line; and

[0036] - signalling the device to disconnect from the transmission line,

[0037] Wherein, line measurement is performed on the transmission line during a time period in which the device is disconnected from the transmission line.

[0038] Also provided is an apparatus deployable in a communication network, the apparatus being coupled to a network node via a transmission line, the apparatus comprising a module for:

[0039] - Provide power to network nodes;

[0040] - monitoring at least one electrical parameter of the transmission line; and

[0041] - If a predetermined line condition or power violation is detected, disconnecting the device from the transmission line so that the network node can perform measurements on the transmission line.

[0042] The network may be an xDSL-based network, or another wired network over which a communication protocol may be used. By way of example and not limitation, the apparatus may be included in a terminal or end-user device typically located in customer equipment. In particular, the apparatus may be coupled (or coupled) to a network node via a transmission line. The network node may be a DPU or form part of a DPU, and the transmission line may be an xDSL subscriber line (e.g., a twisted pair).

[0043] In one embodiment, the apparatus is further configured to monitor at least one electrical parameter of the transmission line by:

[0044] applying a predetermined voltage to the transmission line; and

[0045] The measurement indicates the amount of impedance or current on a transmission line.

[0046] In one embodiment, the predetermined line condition comprises an invalid or missing predefined characteristic of the network node, and the module is further configured to detect the predetermined line condition before or during a startup phase before power is provided to the network node.

[0047] In a particular embodiment, the power violation comprises a current drawn by the network node being below or above a predefined limit, and the module is further configured to detect the power violation during an operating phase of the apparatus and during provision of power to the network node.

[0048] In another embodiment, the module is further configured to disconnect the device from the transmission line by:

[0049] Stopping power supply to the network node; and

[0050] Provide a (sufficiently high) impedance on the transmission line so as not to affect the line measurement (eg MELT); or in other words, high enough to not (significantly) affect the line measurement.

[0051] In one embodiment, the high impedance on the transmission line can be determined according to various requirements and can be achieved by using any appropriate means, as will be understood by those skilled in the art. In one embodiment, the (sufficiently high) impedance can be determined according to the requirements for performing MELT measurements, as defined in ITU-T G.996.2 (the entire contents of which are incorporated herein by reference). For example, a sufficiently high impedance can be a resistance of tens of megohms and a capacitance of less than a few hundred picofarads (e.g., 500pF). In general, the impedance value should be high enough so that it can prevent current from being injected into the device from a network node. In addition, the impedance introduced on the transmission line by the disconnected device can introduce errors in the MELT measurement. In this case, the error should be, for example, twice lower than the predefined accuracy of the MELT measurement. By way of example and not limitation, the test parameters for MELT testing can be found in ITU-T G.996.2, particularly in Tables E1, E2, E3, E4, and E5, which specify the accuracy required for MELT measurements. So configured, in particular by showing a (sufficiently) high impedance on the transmission line, the device can be seen as "virtually" disconnected from the network nodes on the other side of the transmission line without actually being "physically" disconnected from the transmission line. Thus, the device can still continue to monitor the transmission line (e.g., its electrical parameters) even if it is (virtually) disconnected from the transmission line. Furthermore, since the device stops providing power on the transmission line after disconnection, the network nodes can apply measurements (or other operations if necessary) without being affected.

[0052] In one embodiment, the module is further configured to disconnect the device from the transmission line for a predefined time period and reconnect back to the transmission line after expiration of the predefined time period.

[0053] In another embodiment, the module is further configured to:

[0054] After the device is disconnected from the transmission line, monitoring at least one second electrical parameter of the transmission line; and

[0055] If the device detects another predetermined line condition by monitoring at least one second electrical parameter of the transmission line, the device is reconnected back to the transmission line.

[0056] In one embodiment, as will be appreciated by those skilled in the art, power may be provided using RPF or any other suitable means. In particular, RPF is defined in ETSI TS 101 548-1 (incorporated herein by reference in its entirety). By way of example and not limitation, the at least one electrical parameter of the transmission line may be resistance, capacitance, impedance, current, voltage, combinations thereof, and the like.

[0057] The apparatus may be disconnected from the transmission line so that measurements of the transmission line may be performed by the network node. For example, the line measurement may be MELT as described above or any other suitable test / measurement (or in some cases any other suitable operation). Optionally, the end-user device (including the apparatus) may further include a module (e.g., a communication unit) for facilitating communication (e.g., data signaling, xDSL, etc.) between the network node and the end-user device via the transmission line. That is, communication between the network node and the end-user device (including the apparatus) and power supply between the apparatus and the network node may share the same transmission line (or the same conductor included in the transmission line).

[0058] So configured, line measurements (eg, MELT) can be successfully performed by a network node (eg, DPU) on a transmission line in an efficient, flexible, and accurate manner, without being affected (or even prevented) by the power provided by the device.

[0059] In some examples, the quantity indicative of impedance or current may be the measured impedance or current itself, or any other suitable indicative metric (eg, voltage).

[0060] In some cases, the predefined feature may be, for example, a detection feature or a classification feature. As will be appreciated by those skilled in the art, the detection and / or classification feature may be represented in the form of a predefined resistance (or capacitance) feature or a predefined range of allowed voltage and / or current.

[0061] In one embodiment, the module of the device may be further configured to detect a predetermined line condition before or during a startup phase before providing power to the network node. Generally speaking, the startup phase is used to perform certain (startup) protocols (e.g., MDSU protocols) to provide convenient and reliable checks before providing power to the network node. In other words, no (reverse) power is supplied from the device to the network node before the startup phase is successfully completed.

[0062] In some examples, a power violation may include a current drawn by a network node being below or above a predefined limit. For example, if a power constraint is defined as a minimum value / limit (e.g., maintaining a power signature current), a violation of such a power constraint may be drawing no current or drawing a current less than the minimum value / limit (e.g., maintaining a power signature current). In contrast, if a power constraint is defined as a maximum value / limit (e.g., continuous output power), a violation of such a power constraint may be drawing an excess current higher than allowed according to the maximum value / limit (e.g., maintaining a power signature current). In particular, a power violation may be detected during a normal operating phase when power is provided from the device to a network node.

[0063] So configured, detection of an invalid (or missing) predefined signature and / or a violation of a power constraint on the transmission line may be used by the device as an indication (or trigger) to disconnect itself from the transmission line.

[0064] In some examples, a module of the device may be configured to disconnect the device from the transmission line within a predefined time period (e.g., 20 seconds) and reconnect itself (e.g., automatically) after the predefined time period has expired. In general, the predefined time period may be configured to be long enough for performing a line measurement, or in some cases, a set of line measurements performed by a network node.

[0065] In some examples, the module of the device may be further configured to monitor at least one second electrical parameter of the transmission line (or other electrical parameters if necessary) after the device is disconnected from the transmission line. In particular, if the device detects another predetermined line condition by monitoring at least one second electrical parameter of the transmission line, the device (the module) may be further configured to (e.g., actively) reconnect the device to the transmission line. Reconnecting the device back to the transmission line may be performed before the expiration of a predefined time period (e.g., 20 seconds), i.e., before the device itself reconnects. In particular, in some cases, the predefined time period may be relatively long, or even too long, for network nodes that will not have power provided from the device in the case of measurement / testing. Therefore, the process of reconnecting the device back to the transmission line (long before the expiration of the predefined time period) may be considered useful or beneficial in some scenarios.

[0066] In some examples, the additional predetermined line condition may include at least one of an AC signal or a predetermined DC voltage (e.g., 50 or 60V). In particular, the AC signal may be considered to indicate a power level supported by the network node. The power level may be defined, for example, in the form of a maximum power supported, a DC voltage, a line current, or a combination thereof; or, as will be appreciated by those skilled in the art, may be defined in any other suitable manner. An example (but not limited to) of a possible definition of a power level may be the RPF levels SR1, SR2, and SR3 specified in ETSI TS 101 548-1. Correspondingly, as will be appreciated by those skilled in the art, by decoding (or detecting) the AC signal, the device may verify that a network node exists and that the (e.g., RPF) level of the device matches the (e.g., RPF) level of the network node. Similarly, the DC voltage may be predetermined to be sufficiently high (e.g., 50 or 60V) so that by detecting the predetermined (sufficiently high) DC voltage, the device can verify that: 1) there is no short circuit, as a short circuit would lower the DC voltage; 2) there is no off-hook phone, as an off-hook phone would lower the DC voltage; 3) there is no open circuit, otherwise there would be no DC voltage on the device side. More specifically, the DC portion may be set on a transmission line with a high output impedance, so that any off-hook phone would lower the voltage on the line. For example, the AC signal may be represented in the form of an FSK or AM signal with a sine wave frequency in the range of 1kHz to 2.5kHz. Of course, other suitable signals may be used or defined, such as different formats and / or combinations, so as to be able to reconnect the device back to the transmission line.

[0067] In some examples, the modules of the device may include at least one processor and at least one memory including computer program code, the at least one memory and the computer program code being configured to: together with the at least one processor, cause the device to at least provide power to a network node; monitor at least one electrical parameter of a transmission line; and if a predetermined line condition or power violation is detected, disconnect the device from the transmission line so that the network node can perform measurements on the transmission line.

[0068] As another main aspect, a method of operating a network node is provided. The network node may be coupled (coupled) to a device as described above via a transmission line. In particular, the method may include: receiving power from the device via the transmission line; performing line measurements on the transmission line; and signaling the device to disconnect from the transmission line. More specifically, performing line measurements on the transmission line during a period of time when the device is disconnected from the transmission line.

[0069] As another main aspect, a method of operating an apparatus is provided. As described above, the apparatus may be couplable (coupled) to a network node via a transmission line. In particular, the method may include: providing power to the network node; monitoring at least one electrical parameter of the transmission line; and if a predetermined line condition or power violation is detected, disconnecting the apparatus from the transmission line so that the network node can perform measurements on the transmission line.

[0070] In particular, the details of the disclosed method may be implemented as a computer program, which may also be stored on a non-transitory computer-readable medium including program instructions.

[0071] In particular, it will be appreciated that the methods according to the present disclosure relate to methods of operating network nodes and / or devices according to the above-described example embodiments and variations thereof, and that corresponding statements made about the devices are equally applicable to the corresponding methods, such that similar descriptions may be omitted for the sake of brevity. In addition, even if not explicitly disclosed, the above aspects may be combined in many ways. The skilled person will appreciate that these combinations of aspects and features / steps are possible unless they produce conflicts that are clearly excluded.

[0072] It should also be understood that in this document, the terms "couple" or "coupled" refer to elements that are in electrical communication with each other, whether directly connected, such as via wires, or in some other manner (such as indirectly). It is worth noting that an example of coupled is connected.

[0073] Implementations of the disclosed apparatus may include the use of, but are not limited to, one or more processors, one or more application specific integrated circuits (ASICs), and / or one or more field programmable gate arrays (FPGAs). Implementations of the apparatus may also include the use of other conventional and / or custom hardware, such as a software programmable processor.

[0074] Other and further example embodiments of the present disclosure will become apparent during the following discussion and with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] The following is an exemplary description of the embodiments of the present disclosure with reference to the accompanying drawings, in which

[0076] Figure 1a Schematically illustrates a high-level example of a network system according to an embodiment of the present disclosure;

[0077] Figure 1b Another high-level example of a network system according to an embodiment of the present disclosure is schematically shown;

[0078] Figure 2 Schematically illustrates an example of a network system according to another embodiment of the present disclosure;

[0079] Figure 3 Schematically illustrates an example of a network system according to another embodiment of the present disclosure;

[0080] Figure 4 An example of a network system according to yet another embodiment of the present disclosure is schematically shown;

[0081] Figure 5 schematically illustrates an example of a flow chart according to an embodiment of the present disclosure; and

[0082] Figure 6 An example of a flowchart according to another embodiment of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0083] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings. In particular, the same elements in the drawings may be indicated by the same (or similar) reference numerals, and thus repeated descriptions thereof may be omitted for the sake of brevity.

[0084] Figure 1a Schematically illustrated is a high-level example of a network node 1100 coupled to a device 1250 via a communication (or transmission) line 1300. The communication line 1300 forms part of a wired communication network over which a wired communication protocol may occur, such as any suitable wired network technology over twisted pair, coaxial cable, etc., such as ADSL, VDSL, G.Fast, MG.Fast, etc.

[0085] Figure 1b It shows the formation of Figure 1b The apparatus 1250 is shown as a portion of an end-user device designated as 1200, wherein the end-user device 1200 further includes a module 1240 configured to be communicatively coupled to a communication module 1140 also included in the network node 1100. Both the communication modules 1240 and 1140 are configured to communicate over the transmission line 1300 using the wired communication protocol.

[0086] Therefore, the network node 1100 is usually located at the operator side of the communication network 1000, and the device 1250 is usually located at the customer equipment of the communication network 1000. For example, the network node 1100 may be a DPU, and the device 1250 may be a power supply unit in the end-user device 1200. In addition, as Figure 1bAs shown, the network node 1100 and the end-user device 1200 may be coupled (or connected) via a transmission line 1300 (e.g., an xDSL subscriber line (e.g., a twisted pair)). As described above, the transmission line 1300 may be used to exchange data signals between the network node 1100 and the end-user device 1200, and to transmit power from the device 1250 to the network node 1100. It is worth noting that this power supply from the customer side to the network side may be referred to as RPF.

[0087] More specifically, the network node 1100 may include a module 1150 for: receiving power from the device 1250 via the transmission line 1300; performing line measurements on the transmission line; and signaling the device to disconnect from the transmission line.

[0088] exist Figure 1b In the illustrated embodiment, the module 1150 is shown as including three separate functional units 1110, 1120, and 1130, but in other embodiments, other configurations are possible.

[0089] exist Figure 1b In an embodiment of the present invention, the module 1110 is configured to receive power from the device 1250 via the transmission line 1300. The module 1120 is configured to perform line measurements on the transmission line 1300. The line measurements may be MELT measurements. In addition, the network node 1100 may further include a module 1130 for signaling the device 1250 to disconnect from the transmission line 1300. It is worth noting that the module 1120 may be further configured to perform line measurements on the transmission line 1300 during a period of time when the device 1250 is disconnected from the transmission line 1300.

[0090] Similarly, on the other side, Figure 1a The apparatus 1250 may include means for: providing power to a network node; monitoring at least one electrical parameter of a transmission line; and if a predetermined line condition or power violation is detected, disconnecting the apparatus from the transmission line so that the network node can perform measurements on the transmission line.

[0091] exist Figure 1b In an embodiment of the present invention, the device 1250 is depicted as including three separate modules: a module 1210 for providing power to the network node 1100 via the transmission line 1300, a module 1220 for monitoring at least one electrical parameter of the transmission line 1300 (such as a quantity indicating impedance, current, etc.), and a module 1230 for disconnecting the device 1250 from the transmission line 1300 if a predetermined line condition or power violation is detected, so that the network node 1100 can perform measurements (e.g., MELT) on the transmission line 1300.

[0092] Broadly speaking, the present disclosure proposes a simple mechanism driven by a network node 1100 (e.g., a DPU) to disconnect (and optionally reconnect) a device 1250 from a transmission line 1300 so that (e.g., MELT) measurements can be performed by a measurement module 1120 (which can be implemented as any suitable test / measurement circuit) of the network node 1100. In other words, in order for the network node 1100 to be able to perform a MELT measurement, it will instruct the device 1250 to stop providing power and disconnect itself from the transmission line 1300, and possibly provide a (sufficiently) high impedance to the line 1300 so that the device 1250 does not (significantly) affect the capacitance, resistance, and external voltage measurements made by the measurement module 1120 within the network node 1100. In particular, the impedance should be high enough to not (significantly) affect the line measurements (e.g., MELT), and this can be achieved in any suitable way. As will be appreciated by those skilled in the art. In one embodiment, the (sufficiently high) impedance may be determined according to the requirements for performing the MELT measurement, as defined in ITU-T G.996.2 (the entire contents of which are incorporated herein by reference). For example, a sufficiently high impedance may be a resistance of the order of tens of megohms, and a capacitance of less than a few hundred picofarads (e.g., 500 pF). In general, the impedance value should be high enough so that it can prevent current injection from the network node to the device. In some cases, the impedance introduced on the transmission line 1300 by the disconnected device 1250 may introduce an error in the MELT measurement. In this case, the error should be, for example, twice lower than the predefined accuracy of the MELT measurement. By way of example and not limitation, test parameters for MELT testing may be found in ITU-T G.996.2, in particular in Tables E1, E2, E3, E4, and E5, which specify the accuracy required for MELT measurements. ITU-T G.996.2, in particular in Tables E1, E2, E3, E4, and E5, are incorporated herein by reference.

[0093] Figure 2 An example of a network system 2000 according to another embodiment of the present disclosure is schematically shown.

[0094] like Figure 2As shown, the network system 2000 may include a network node 2100, which is usually located at the operator side, and a terminal node (or end-user device) 2200, which is usually located at the customer equipment. For example, the network node 2100 may be a DPU. In addition, the network node 2100 and the terminal node 2200 may be coupled (or connected) via a transmission line 2300, such as an xDSL subscriber line. As described above, the transmission line 2300 may be used to exchange data signals between the network node 2100 and the terminal node 2200, and may be used to transmit power from the terminal node 2200 (or in particular from the power supply unit 2250 of the terminal node 2200) to the network node 2100. In particular, the power supply unit 2250 may correspond to the power supply unit 2250 as shown in FIG. Figure 1a and 1b The embodiment of the device / power supply unit 1250 is shown. It is worth noting that this power supply from the customer side to the network side can be called RPF.

[0095] In particular, the terminal node 2200 (or in particular the power supply unit 2250) may include a PSE 2202 configured to inject power into the transmission line 2300 via the PS 2201. The terminal node 2200 may further include an xDSL network termination equipment (hereinafter abbreviated as NTE in this document) 2203 configured to communicate xDSL broadband signals with the network node 2100 via the transmission line 2300. The PS 2201 may then be further configured to separate the power and the xDSL broadband signal. It is worth noting that even in Figure 2 In the current example, the power supply unit 2250 is integrated in the terminal node 2200. In some other cases, the power supply unit 2250 may also be implemented as an independent device (or apparatus). Figure 2 Not explicitly shown in this example, the terminal node 2200 may also include any other suitable components and / or circuits according to various situations or requirements. As an example and not a limitation, the terminal node may optionally include a backup power supply for providing backup power in the event of a power failure; or a power control unit (or circuit) for controlling power management behavior during, for example, the startup and operation phases.

[0096] Similarly, on the other side, the network node 2100 may include a PE 2102 coupled to the transmission line 2300 using a PS 2101, which is configured to extract power delivered from (the power supply unit 2250 of) the terminal node 2200. In addition, the node 2100 may also include an xDSL NTE 2103, which is configured to communicate xDSL broadband signals with the terminal node 2200 through the transmission line 2300 with the help of the PS 2101. In order to monitor the quality of the transmission line 2300 and debug potential problems in the field, the network node may further include a module 2110 for performing line measurement MELT.

[0097] Broadly speaking, the present disclosure proposes a simple mechanism driven by a network node 2100 (e.g., a DPU) to disconnect (and optionally reconnect) a PSE 2202 or a power supply unit 2250 from a transmission line 2300 so that MELT measurements can be performed by a MELT block 2110 (e.g., implemented as a suitable test / measurement circuit) of the network node 2100. In other words, in order for the network node 2100 to perform a MELT measurement, it will instruct the PSE 2202 (or, in particular, the power supply unit 2250) to stop providing power and disconnect itself from the transmission line 2300, and possibly present a sufficiently high impedance to the line 2300 so that the PSE 2202 (or the power supply unit 2250) does not (significantly) affect the capacitance, resistance, and external voltage measurements made by the MELT circuit 2110 within the network node 2100.

[0098] Therefore, in Figure 2 In the example embodiment of , the terminal node 2200 (particularly the power supply unit 2250) may further include a PSE disconnect block 2220, and the network node 2100 may further include a detection feature block 2121, a classification feature block 2122, and a PSE disconnect block 2120. In particular, as described above, the detection and classification feature blocks 2121 and 2122 may be configured to generate predefined detection and classification features, respectively.

[0099] On the other hand, the PSE disconnect block 2220 may be configured to disconnect the power supply unit 2250 from the transmission line 2300; and the PE disconnect block 2120 may be configured to disconnect (or prevent) the PE 2102 and / or possible detection and classification features 2121 and 2122 from the transmission line 2300 according to various circumstances (e.g., a particular stage of operation of the network system).

[0100] When the network node 2100 wants to perform MELT measurements (e.g., periodically or triggered), the network node 2100, in particular the PE disconnection block 2120, may be operated (or configured) to disconnect the corresponding block of the network node 2100, depending on which operation phase the network system is in. For example, if the terminal node 2200 (or the power supply unit 2250) has not yet started or is starting up, the PE disconnection block 2120 may be configured to disable the detection and / or classification features 2121 and 2122 on the line 2300. Therefore, the disconnection of the detection / classification features 2121 and 2122 may prevent the power supply unit 2250 from starting up. On the other hand, if the power supply unit 2250 is already supplying power to the network node 2100 (i.e., during the normal operation phase), the PE disconnection block 2120 may be configured to completely or partially prevent the PE 2102 from drawing (or extracting) power from the power supply unit 2250. That is, for example, the network node 2100, and in particular the PE 2102 therein, may be configured not to draw any current or to draw a current below a predefined current limit from the power supply unit 2250. For example, the predefined limit may be a maintenance power signature current.

[0101] On the other hand, the terminal node 2200 (or in particular the power supply unit 2250) may be configured to disconnect itself from the transmission line 2300, for example by means of the PSE disconnect block 2220, after detecting an invalid or missing detection and / or classification feature during a startup procedure of the power supply unit 2250, or after detecting a power violation (e.g., a violation of the maintain power feature) during normal operation of the power supply unit 2250 when the power supply unit 2250 has supplied power to the network node 2100. In particular, the power supply unit 2250 or the terminal node 2200 may, for example, disconnect itself from the transmission line 2300 with the aid of an additional monitoring module (e.g. Figure 1b The monitoring module 1220 in the transmission line 2300 is further configured to monitor at least one electrical parameter of the transmission line 2300, such as a quantity indicating impedance, current, etc.

[0102] In some cases, power supply unit 2250 may be disconnected from transmission line 2300 for a certain (eg, predefined) period of time (which may be referred to as a MELT wait time) (eg, within 20 seconds).

[0103] After the MELT wait time period expires, the power supply unit 2250 (or the terminal node 2200) may be configured to reconnect itself back to the line 2300. As will be appreciated by those skilled in the art, such reconnection may require the power supply unit 2250 to, for example, perform a boot process (e.g., MDSU boot protocol) again before being able to provide power to the network node 2100.

[0104] Obviously, the network node 2100 can use the MELT waiting period to perform MELT measurement, or perform any other suitable operation if necessary. In particular, the network node 2100 can detect the disconnection of the power supply unit 2250 by monitoring the line voltage or any other suitable quantity indicating the line voltage (e.g., current or resistance). In addition, the network node can also release any residual (e.g., RPF) voltage on the transmission line 2300 before performing the MELT measurement to ensure that the measurement result is reliable and may not be affected by any residual voltage on the line 2300.

[0105] It should also be noted that in order to perform MELT measurements, the network node (e.g., DPU) typically requires power. Since the power supply is stopped after the power supply unit 2250 is disconnected, the network node can try to use power from another transmission line or from a set of transmission lines that reverse power the network node. Alternatively, when only the line to be tested is powering the network node, the network node can rely on a (e.g., internal) backup power supply to perform MELT measurements. In order to reduce power requirements, the network node can also stop providing xDSL service to the line under test.

[0106] It should also be noted that only in a single-box scenario, where the power supply unit and the NTE are integrated together, the xDSL line can be used as a communication channel for the DPU to request the power supply unit to disconnect it from the twisted pair. This requires that the xDSL line is operational, which is not always the case when using MELT to debug field problems. In a two-box model, that is, when the power supply unit is a separate device, there is no such communication channel. In particular, the present disclosure does not rely on the DSL function. The communication for disconnection and reconnection from the DPU to the PSE does not use the communication function of the DSL. Therefore, the present disclosure is also applicable to a two-box scenario, where the power supply unit and the NTE are located in separate boxes in the customer equipment, and there is no active communication between the power supply unit and the NTE. In addition, in a single-box scenario (i.e., the power supply unit and the NTE are integrated in one box), the communication for requesting disconnection can also be accomplished by, for example, using the DSL communication through the OAM (operation and maintenance) channel of the NTE at the customer equipment. In this case, the NTE can communicate with the power supply unit to disconnect from the line. However, this requires that the function of the DSL communication is active, which is not always present when there is a problem with the communication line. To avoid dependence on DSL functionality, the present disclosure may be used in a single box scenario.

[0107] Figure 3 Schematically illustrates an example of a network system 3000 according to another embodiment of the present disclosure. In particular, Figure 3 The same or similar reference numerals in the drawings indicate Figure 2The network system 2000 is shown with the same or similar elements, so that repeated description thereof may be omitted for the sake of brevity.

[0108] and Figure 2 Similar to Network System 2000, Figure 3 The network system 3000 may include an xDSL NTE 3203, a PSE 3202, a PSE disconnection block 3220, and a PS 3201 in a terminal node 3200 on a customer equipment side; and a MELT block 3110, an xDSL NTE 3103, a PS 3101, a PE disconnection block 3120, a PE 3102, a detection feature block 3121, and a classification block 3122 in a network node 3100 on a network side. In particular, the PSE 3202 and the PSE disconnection block 3220 may be included in a similar Figure 2 In the power supply unit 3250 of the power supply unit 2250.

[0109] However, with Figure 2 Compared with Network System 2000, Figure 3 The network node 3100 may further include an additional excess line current block 3130 .

[0110] So arranged, the PSE disconnect block 3220 can be configured to provide a disconnection of the power supply unit 3250 from the transmission line 3300 and can operate as described above. In addition, the PE disconnect block 3120 can be configured to provide a disconnection of the PE 3102 and / or the detection / classification features 3121 and 3122 from the transmission line 3300 and can operate at the beginning of the MELT measurement to avoid affecting the MELT measurement. Finally, the excess line current block 3130 can be configured to provide the required excess line current to force the power supply unit 3250 to be disconnected from the transmission line 3300.

[0111] Thus, when the network node 3100 wants to perform MELT measurements (e.g., periodically or triggered), particularly if the power supply unit 3250 has not yet been started or is starting up, the network node 3100 and particularly the PE disconnect block 3120 therein may be operated (or configured) to disable the detection and / or classification features 3121 and 3122 on the line 3300.

[0112] On the other hand, if the power supply unit 3250 is already supplying power to the network node 3100 (i.e., during a normal operation phase), the network node 3100, and in particular the excess line current block 3130 therein, may be configured to draw an excess line current from the power supply unit 3250, violating a (second) predefined power limit of the power supply unit 3250. The (second) predefined power limit may be a continuous output power limit of the power supply unit 3250. That is, for example, the network node 3100, and in particular the excess line current block 3130 together with the PE 3102 may be configured to draw a current from the power supply unit 3250 that is higher than the (second) predefined limit (e.g., continuous output power).

[0113] Correspondingly, the terminal node 3200 (or in particular the power supply unit 3250) may be configured to disconnect itself from the transmission line 3300 for a certain period of time (which may be referred to as the MELT wait time), for example 20 seconds, after detecting an invalid or missing detection and / or classification feature during the startup phase of the power supply unit 3250 or after detecting a power violation (e.g., a violation of continuous output power) during the normal operation phase of the power supply unit 3250 when the power supply unit 3250 has been supplying power to the network node 3100. As will be appreciated by those skilled in the art, this may be achieved by monitoring (using any suitable module or circuit) at least one electrical parameter (e.g., resistance, current, etc.) of the transmission line 3300.

[0114] After the MELT wait time period expires, the power supply unit 3250 (or the terminal node 3200) may be configured to reconnect itself back to the line 3300. As will be appreciated by those skilled in the art, such reconnection may require the power supply unit 3250 to, for example, perform a startup procedure (e.g., an MDSU startup protocol) before being able to provide power to the network node 3100 again.

[0115] It is worth noting that the network node 3100 can utilize the MELT waiting period to perform MELT measurements or perform any other suitable operations if necessary. In particular, the network node 3100 can detect the disconnection of the power supply unit 3250 by monitoring the line voltage or any other suitable quantity (e.g., current or resistance) indicating the line voltage. In addition, the network node 3100 can also discharge any residual RPF voltage on the transmission line 3300 before performing the MELT measurement to ensure reliable measurement results.

[0116] It should also be noted that in some cases, the maximum allowed time for a single or combined MELT measurement set may be set to a relatively long period of time (e.g., 20 seconds or longer) that a network node (e.g., DPU) is without power from the PSE of the line under test. Thus, the PSE may be required to reconnect itself back to the line and resume powering the DPU even before the predefined disconnection time period expires. In some cases, this reconnection of the PSE to the transmission line may be performed bypassing the MDSU startup protocol.

[0117] Figure 4 Schematically illustrates an example of a network system 4000 according to an embodiment of the present disclosure. In particular, Figure 4 The same or similar reference numerals in the drawings indicate Figure 2 The network system 2000 is shown with the same or similar elements, so that repeated description thereof may be omitted for the sake of brevity.

[0118] from Figure 4 It can be seen that in the network system 4000, in particular in the power supply unit 4250, a reconnection detection block 4230 may be further included. In particular, the reconnection detection block 4230 may be configured to continue monitoring the electrical parameters (e.g., line voltage) of the transmission line 4300 when the power supply unit 4250 is disconnected. The reconnection detection block 4230 may be configured to reconnect the power supply unit 4250 back to the transmission line 4300 when a predetermined line condition is detected (or decoded). For example, in some cases, since the network node may include a suitable MELT circuit that can introduce AC and DC voltages on the line, the predefined line condition may include specific voltage signaling (e.g., generated using a MELT circuit), which may include an AC part and a DC part. In particular, as described above, the AC part may convey the (supported) power level of the network node; and the DC part may be used to detect an off-hook phone on the twisted pair line. That is, by decoding (or detecting) the AC signal, the power supply unit 4250 can verify that the DPU (network node 4100) is present and that the PSE RPF power level matches the DPU RPF power level. Similarly, by detecting a (sufficiently high) DC voltage (e.g., 50 or 60V), the power supply unit 4250 (particularly through the reconnection detection block 4230) can verify that: 1) there is no short circuit, because a short circuit will reduce the DC voltage; 2) there is no off-hook phone, because an off-hook phone will reduce the DC voltage; and 3) there is no open circuit, otherwise there will be no DC voltage on the PSE side. More specifically, the DC section can be set on a transmission line with a high output impedance so that any off-hook phone will reduce the voltage on the line.

[0119] So configured, the power supply unit 4250 may be configured to reconnect back to the transmission line 4300 and possibly (e.g., immediately) power the network node 4100 when the supported (e.g., RPF) power level is decoded from the AC signal and a predetermined DC voltage is detected. In some cases, the DC voltage may be predetermined to be high enough (e.g., 50 or 60V) to indicate that there is no off-hook phone. However, as will be appreciated by those skilled in the art, any other suitable signal or combination thereof may be used to be defined as a line condition to be detected so that it can be easily detected by the power supply unit 4250 (particularly by the reconnection detection block 4230) and reliably regarded as a trigger to reconnect to the transmission line 4300.

[0120] It is worth noting that even if Figure 4 The reconnection mechanism shown applies to Figure 2 It is also obvious to those skilled in the art that this reconnection mechanism can be similarly applied to Figure 3 network system (possibly with minor adaptation).

[0121] Figure 5 An example of a flowchart of an MDSU startup procedure for a PSE and a DPU according to an embodiment of the present disclosure as given in TS 101 548-1 is schematically shown. In particular, Figure 5 The schematic diagram shows the MDSU startup process that can be applied in conjunction with the MELT function between the PSE (or in particular the power supply unit) on the customer equipment side and the DPU on the operator side. In this sense, Figure 5 The "PSE" in can be considered to correspond to Figure 2 or 3 in the power supply unit 2250 or 3250 (including the respective PSE 2202 or 3202 and the PSE disconnect block 2220 or 3220); and Figure 5 The "DPU" in can correspond to Figure 2 or 3 in the corresponding network node 2100 or 3100. In addition, it should be noted that Figure 5 As shown in the legend of the DPU in Figure 1, white blocks indicate behavior in normal mode (or in other words, no MELT measurement is required); striped boxes indicate behavior that initializes or triggers MELT measurement, as shown above. Figure 2 and Figure 3 shown.

[0122] Below, only selected blocks / steps from the complete flow chart (which are considered to be more relevant to the present disclosure) will be described. However, other blocks / steps may be considered obvious to those skilled in the art, so that their corresponding descriptions may be omitted for brevity.

[0123] In particular, as from Figure 5As can be seen, the process can start with the power supply unit in an idle (or powered off) state in 5000. At startup, the power supply unit can go through a process 5010 for detecting and evaluating a detection feature as described above. During this process 5010, depending on whether a MELT measurement is to be performed, the DPU (or network node) on the other side of the transmission line can be configured to behave in 5110. For example, in a normal mode where no MELT measurement is expected, the DPU can be configured to signal a detection feature as defined; whereas if a MELT measurement is to be performed, the DPU can be configured to avoid signaling any valid detection features as described above.

[0124] Similarly, in the subsequent process 5020, the classification features will be detected and evaluated. On the other hand, the DPU can be configured to behave in 5120 accordingly depending on whether a MELT measurement is to be performed. In particular, in a normal mode where no MELT measurement is expected, the DPU can be configured to signal the defined classification features; whereas if a MELT measurement is to be performed, the DPU can be configured to avoid signaling any valid classification features as described above.

[0125] If the detection feature and the classification feature are successfully detected, the power supply unit may be configured to start supplying power to the DPU in 5030 and enter a normal operation phase.

[0126] If during normal operation, a violation of the power supply constraints executed by the DPU in 5140 is detected by the power supply unit in 5040 , the power supply unit may be configured to stop providing power to the DPU in 5050 .

[0127] If any of the error conditions shown above are detected, the power supply unit may be configured to disconnect from the transmission line in 5060. The power supply unit may be configured to disconnect for a period of time according to the MELT wait timer in 5070, and when the timer expires, the power supply unit may be configured to reconnect itself back to the transmission line in 5080 and return to the idle state of 5000.

[0128] Figure 6 Schematically shows an example of a flowchart of an MDSU startup process for PSE and DPU according to another embodiment of the present disclosure and also according to TS 101 548-1. In particular, Figure 6 The same or similar reference numerals in the drawings indicate Figure 5 The same or similar elements in the illustrated flowcharts may be omitted for the sake of brevity.

[0129] More specifically, Figure 5 Compared with the flowchart, Figure 6Additionally shown is a reconnection process 6090, in which, as detailed above, if a predefined line condition is detected, the power supply unit (e.g., Figure 4 The power supply unit 4250) can be configured to reconnect itself to the transmission line. In this way, the power supply unit may not need to wait until the predefined MELT waiting time expires, and if certain line conditions are met, the power supply unit may be able to (actively) reconnect, thereby improving the overall efficiency of the network system.

[0130] The disclosed example embodiments may be implemented in many ways using hardware and / or software configurations. For example, the disclosed embodiments may be implemented using dedicated hardware and / or hardware associated with software executable thereon. The components and / or elements in the accompanying drawings are examples only and do not limit the scope of use or functionality of any hardware, software in combination with hardware, firmware, embedded logic components, or a combination of two or more such components that implement a specific embodiment of the present disclosure.

[0131] It should be noted that the terms "coupled" and "coupleable" should not be interpreted as being limited to direct connections. Therefore, the scope of the expression "device A coupled to device B" should not be limited to devices or systems in which the output of device A is directly connected to the input of device B, and / or vice versa. This means that there is a path between the output of A and the input of B, and / or vice versa, which may be a path that includes other devices or modules.

[0132] As used in this disclosure, the term "circuitry" may refer to one or more or all of the following: (a) pure hardware circuit implementations (such as implementations solely in analog and / or digital circuits) and (b) combinations of hardware circuits and software, such as (as applicable): (i) a combination of analog and / or digital hardware circuits and software / firmware, and (ii) any portion of a hardware processor (including a digital signal processor) with software, software, and memory that work together to enable an apparatus such as a server or user equipment to perform various functions, and (c) hardware circuits and / or processors (e.g., a microprocessor or a portion of a microprocessor) that require software (e.g., firmware) to operate, but the software may not be present when the software is not required for operation.

[0133] This definition of circuitry applies to all uses of this term in this disclosure, including in any claims (if applicable). As another example, as used in this disclosure, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware.

[0134] It should also be noted that the description and the accompanying drawings illustrate only the principles of the present disclosure. Those skilled in the art will be able to implement various arrangements that, although not explicitly described or illustrated herein, embody the principles of the present disclosure and are included in its spirit and scope. In addition, all examples and embodiments outlined in the present disclosure are primarily intended to be explicitly for illustrative purposes only, to help the reader understand the principles of the proposed methods. In addition, all statements of the principles, aspects, and embodiments of the present disclosure and specific examples thereof are provided herein and are intended to encompass their equivalents.

Claims

1. A network node capable of being coupled to a device via a transmission line, the network node comprising means for: - receiving power from said device via said transmission line; - performing line measurements on said transmission line; and - signalling to said device to disconnect from said transmission line, wherein the module is further configured to perform the line measurement on the transmission line during a time period when the device is disconnected from the transmission line; in, The module is also configured to: applying an invalid predefined feature or no predefined feature to the transmission line; or A power constraint for drawing power provided from the device is violated.

2. The network node according to claim 1, wherein: The module is further configured to apply invalid predefined features or not apply predefined features before or during a startup phase of receiving the power from the device.

3. The network node according to claim 1, wherein: The module is further configured to perform a violation of the power constraint by drawing a current from the transmission line below or above a predefined limit, and wherein the violation of the power constraint is performed during an operation phase of the network node and receiving the power supply from the device.

4. The network node according to any one of claims 1 to 3, wherein: The module is also configured to detect disconnection of the device from the transmission line by monitoring a quantity indicative of a voltage on the transmission line.

5. The network node according to any one of claims 1 to 3, wherein: The module is also configured to signal the disconnected device via the transmission line to reconnect the device back to the transmission line.

6. The network node according to claim 5, wherein: The module is also configured to signal the device to reconnect back to the transmission line by applying at least one of an AC signal or a predetermined DC voltage to the transmission line.

7. A device capable of being coupled to a network node via a transmission line, the device comprising means for: - Providing power to the network nodes; - monitoring at least one electrical parameter of the transmission line; and - if a predetermined line condition or power violation is detected, disconnecting the device from the transmission line so that the network node can perform measurements on the transmission line, in, The predetermined line condition comprises an invalid predefined characteristic or an absence of a predefined characteristic of the network node, and wherein the module is further configured to detect the predetermined line condition before or during a startup phase before providing power to the network node.

8. The device according to claim 7, wherein: The module is further configured to monitor the at least one electrical parameter of the transmission line by: applying a predetermined voltage to the transmission line; and The measurement indicates a quantity of impedance or current on the transmission line.

9. The device according to any one of claims 7 to 8, wherein: The power violation comprises a current drawn by the network node being below or above a predefined limit and the power violation is detected during an operation phase of the apparatus and during provision of power to the network node.

10. The device according to any one of claims 7 to 8, wherein: The module is also configured to disconnect the device from the transmission line by: Stopping power supply to the network node; and Provide a sufficiently high impedance on the transmission line so as not to affect the line measurement.

11. The device according to any one of claims 7 to 8, wherein: The module is also configured to disconnect the device from the transmission line for a predefined time period and reconnect back to the transmission line after expiration of the predefined time period.

12. The device according to any one of claims 7 to 8, wherein: The module is also configured to: After the device is disconnected from the transmission line, monitoring at least one second electrical parameter of the transmission line; and reconnecting the device back to the transmission line if the device detects another predetermined line condition by monitoring at least one second electrical parameter of the transmission line; The other predetermined line condition includes at least one of an AC signal or a predetermined DC voltage.

13. An end-user device comprising the apparatus according to any one of claims 7 to 12, the end-user device further comprising means configured to communicate with a network node of a communication network via the transmission line.

14. The network node according to any of claims 1 to 6, comprising means for communicating with an end-user device according to claim 13 through the transmission line via a communication network.

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