Patent Description:
This section introduces aspects that may help facilitate a better understanding of the invention. Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is prior art or what is not prior art.

Some submarine power-transmission cables and submarine fiber-optic communication cables may be configured with accelerometers and pressures sensors to detect vibrations and pressure changes characteristic of earthquakes, tsunamis, and other catastrophic events to provide an early-warning system for such events. For example, some submarine fiber-optic communication cables may have spans of optical fibers interconnected by repeaters that amplify the optical signals for transmission from one end of the cable to the other. Such cables typically also have spans of electrically conductive (e.g., metal) wiring that provide electrical power to and electronic signaling to and from the repeaters.

The proposed SMART (Scientific Monitoring And Reliable Telecommunications) technology would involve the provisioning of sensors, such as accelerometers, pressure sensors, and temperature sensors, as an integral part of a submarine fiber-optic communication system for recording scientific measurements that can be used, for example, to detect events such as earthquakes and tsunamis. Such sensors may be implemented as part of the cable repeaters or within the cable itself along the cable spans between repeaters or both. Reliable implementations of SMART technology would be technically complex and expensive. <CIT> discloses a repeater capable of signal amplification while maintaining continuity of a transmission line at a relay point.

In order to address the shortcomings of the prior art, the current invention provides an apparatus according to claim <NUM>. Advantageous embodiments are disclosed in the dependent claims.

Embodiments of the invention will become more fully apparent from the following detailed description, the appended claims, and the accompanying drawings in which like reference numerals identify similar or identical elements.

Detailed illustrative example embodiments of the present invention are disclosed herein. However, specific structural and functional details disclosed herein are merely representative for purposes of describing example embodiments of the present invention. The present invention may be embodied in many alternate forms and should not be construed as limited to only the embodiments set forth herein. Further, the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments of the invention.

It further will be understood that the terms "comprises," "comprising," "includes," and/or "including," specify the presence of stated features, steps, or components, but do not preclude the presence or addition of one or more other features, steps, or components. It also should be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures.

<FIG> is an example of a simplified representation of a cable-with-pods assembly <NUM> according to certain embodiments of the disclosure. Although the techniques of the present disclosure can be implemented in the context of any system having a cable with an electrically conductive core, these techniques are first described with respect to the cable-with-pods assembly <NUM> of <FIG> for a cable-based power-transmission system. Those skilled in the art will understand how to implement the invention in the context of other cable-based systems, such as (without limitation) cable-based communication systems having fiber-optic cables.

As shown in <FIG>, the cable-with-pods assembly <NUM> has a power-transmission cable <NUM> supplied by two PFE (power feed equipment) modules <NUM> that support the transmission of electrical power from either end of the cable to the other over a contiguous, electrically conductive (e.g., copper, aluminum, or other suitable material) core <NUM> that spans the length of the cable <NUM>. Some alternative power-transmission systems may have only one PFE module and therefore transmit power in only one direction. Note that, in some other embodiments, a cable-with-pods assembly might have no PFE modules.

The assembly <NUM> also includes a set of pods <NUM>/<NUM> distributed along the length of the cable <NUM>. In particular, the assembly <NUM> has (i) two terminal pods <NUM> located at (or proximate to) either end of the cable <NUM> near the PFE modules <NUM> and (ii) a number of intermediate pods <NUM>, e.g., evenly, distributed along the length of the cable <NUM> between the two terminal pods <NUM>. In one possible submarine application, the two PFE modules <NUM> and the two terminal pods <NUM> (along with the two corresponding portions of the cable <NUM>) are terrestrial (i.e., located on land), while the intermediate pods <NUM> (along with the rest of the cable <NUM>) are submarine (i.e., located under water).

As explained further below, each pod <NUM>/<NUM> has two shaped portions (not explicitly represented in <FIG>) that enable the pod to be configured (e.g., clamped) around the cable <NUM> without having to modify the cable itself, where the contiguous cable <NUM> passes through an (e.g., cylindrical) opening formed by each assembled pod (as depicted by the broken lines in <FIG>). Those skilled in the art will understand that a pod could have more than two portions and/or the portions could have any suitable shapes that enable the portions to be configured to form an assembled pod surrounding the cable <NUM>. Alternatively, each pod could have a unitary structure with an opening that enables the pod to be slid over an end of the cable and secured at its desired location using some suitable mechanism.

The pods <NUM>/<NUM> are inductively, but not galvanically, coupled to the cable's conductive core <NUM>. In particular, each intermediate pod <NUM> has circuitry (not shown in <FIG>) that enables the pod to magnetically induce electrical signals, e.g., in some implementations, pulses of electrical current, that propagate in both directions along the conductive core <NUM> away from the pod. In addition, current pulses induced in the cable's conductive core <NUM> by another pod and arriving at an intermediate pod <NUM> will magnetically induce electric signals within that intermediate pod that cause the intermediate pod to induce repeated current pulses in the conductive core <NUM>. Similarly, current pulses arriving at a terminal pod <NUM> will magnetically induce electrical signals within that terminal pod that cause the pod to transmit, to the external world, data signals <NUM> corresponding to those current pulses. Note that, although implementations are described below in terms of current pulses, in other implementations, electrical signals other than current pulses, such as (without limitation) low-frequency voltage signals or current waves, could be employed.

Note that, for applications in which the cable independently carries a current, such as in the power-transmission application of <FIG>, the current pulses induced by the pods appear as relatively minor perturbations on the steady-state electrical current corresponding to the power being transmitted through the cable <NUM>. As such, the pods <NUM>/<NUM> can operate without adversely affecting the power-transmission function of the cable <NUM>. Similarly, when the cable is a fiber-optic communication cable, the induced current pulses from the pods appear as relatively minor perturbations on the electrical currents transmitted along the conductive portion of the communication cable. Furthermore, those induced current pulses do not interfere with the optical signals transmitted along the cable's optical fibers. As such, the pods <NUM>/<NUM> can also be used in a cable-with-pods assembly where the cable is a fiber-optic communication cable without adversely affecting the communication function of the cable. Note that, in some other embodiments, the conductive portion of the cable does not carry any independent current.

In certain implementations of the cable-with-pods assembly <NUM> of <FIG>, each intermediate pod <NUM> is powered by a local battery (not shown in <FIG>), such as (without limitation) a LiSOCl<NUM> bobbin-type battery. In order to preserve battery life, each intermediate pod <NUM> may be maintained in a sleep mode during which most of the pod's electrical components are powered down, with at least one exception being the pod's local clock generator (not shown in <FIG>), which runs continuously. Note that, since the terminal pods <NUM> are terrestrial, they can be externally powered and therefore can remain powered on (i.e., in awake mode) continuously. In other implementations, in addition to or instead of being battery-powered, the intermediate pods <NUM> may be able to be externally powered, either from the cable <NUM> itself or from some other suitable external power supply, such as, e.g., an energy harvester harvesting energy from seabed movements.

In some implementations, each intermediate pod <NUM> includes one of more unpowered (i.e., passive) detectors that, upon detection of an event, such as an earthquake or a tsunami, will cause the pod to transition from its sleep mode to its awake mode, during which most if not all of the pod's electrical components are powered on. For example, the one or more passive detectors may include (without limitation) an accelerometer configured to detect an acceleration indicative of an earthquake, a pressure switch configured to detect a pressure change indicative of a tsunami, and/or an acoustic sensor configured to detect acoustic signals indicative of any suitable sound-producing event such as movement near the cable. The intermediate pod <NUM> will then magnetically induce a corresponding sequence of current pulses in the cable's conductive core <NUM> that will be repeated by other pods until the current pulses reach the terminal pods <NUM>. In this way, each intermediate pod <NUM> can independently function as an event detector, and the cable-with-pods assembly <NUM> can function as an early-warning system for earthquakes, tsunamis, and other catastrophic events.

In some implementations, in addition to or instead of the one or more passive detectors, each intermediate pod <NUM> includes one or more powered (i.e., active) sensors, such as accelerometers, pressure sensors, temperature sensors, salinity sensors, pH sensors, etc., that generate measurements of ambient conditions when the pod is in its awake mode. In these implementations, during the awake mode, the pod will magnetically induce a sequence of current pulses in the cable's conductive core <NUM> that represent measurement signals generated by the one or more active sensors, which current pulses are repeated by other pods until the current pulses reach the terminal pods <NUM>. In this way, each intermediate pod <NUM> can independently monitor its local ambient conditions, and the cable-with-pods assembly <NUM> can function as a science monitoring system for ambient conditions across the span of the cable <NUM>.

Depending on the implementation, an intermediate pod <NUM> will automatically transition from its sleep mode to its awake mode in one or more of the following ways: (i) upon detection of an event by a passive detector in the pod, (ii) upon arrival of a sequence of pulses from another pod, and (iii) periodically based on a clock signal generated by the pod's local clock generator.

In certain implementations, each sequence of current pulses initiated by an intermediate pod <NUM> comprises an initial "wake-up" pulse followed, after a specified time delay, by a set of data pulses that encode binary data representing such information as a unique ID number for the initiating pod, the type(s) of passive detector(s) that detected an event, measurement signals generated by one or more active sensors, and/or a time stamp based on the pod's clock generator. In some implementations, a binary value "<NUM>" is represented by a pulse, while the binary value "<NUM>" is represented by the absence of a pulse, where the pulses are transmitted based on a specified clock rate that implies a specified minimum separation time between consecutive pulses. Note that the binary data may include forward error codes or correction codes to improve the reliability of the data transmission.

In one possible implementation, the specified time delay between the wake-up pulse and the start of the set of data pulses is selected to be sufficiently long to ensure that (i) each other intermediate pod <NUM> along the cable <NUM> will be able to repeat the data pulses, when they arrive at that intermediate pod and (ii) each terminal pod <NUM> will be able to convert those data pulses into the corresponding data signal <NUM>. The specified time delay is preferably selected based on the worst-case scenario in which the event-detecting pod is either the first or last intermediate pod <NUM> along the cable <NUM> such that the terminal pod <NUM> at the other end of the cable <NUM> is ensured to be able to process the data pulses by the time those data pulses arrive at that terminal pod.

Whenever an intermediate pod <NUM> receives a wake-up pulse from another pod, the receiving pod will transition from its sleep mode to its awake mode, repeat the wake-up pulse, and then repeat the set of data pulses when they arrive. As explained further below, in preferred implementations, each intermediate pod <NUM> is capable of repeating each received data pulse sufficiently fast such that the repeated data pulse substantially coincides in time with the received data pulse. In this way, each intermediate pod <NUM> operates to effectively amplify the attenuated data pulses as they propagate along the cable <NUM>. Note that a repeated wake-up pulse does not have to substantially coincide with the corresponding received wake-up pulse as they propagate along the cable in the same direction.

In order to ensure that the wake-up and data pulses can be reliably repeated, the intermediate pods <NUM> should be spaced sufficiently closely along the cable <NUM> so that pulses from at least one adjacent pod on either side of an intermediate pod are not too attenuated to be processed when they arrive. Note that, in some implementations, in order for the cable-with-pods assembly <NUM> to be able to continue to function in the event of a single-pod failure, the intermediate pods <NUM> should be spaced closely enough such that each pod is able to repeat pulses received from at least two pods on each side of the pod (for pods having at least two pods on both sides). On the other hand, in order to avoid undesirable echo, the pods should be spaced far enough apart so that the pulses that each pod receives from other, further-away pods are sufficiently attenuated such that those pulses will be too weak to be repeated by the pod.

Since each pulse propagates along the cable <NUM> in both directions, in order to avoid undesirable "echo," in some implementations, when a pod is initiating the transmission of a sequence of pulses, the pod is configured in a "transmit only" mode in which it will not repeat any received pulses until after it has completed the transmission of its sequence of pulses. After a specified time-out period following the last transmitted data pulse, the initiating pod will automatically transition back into its sleep mode or be ready to repeat pulses.

Furthermore, after repeating a received pulse, each other pod will ignore any received pulses for the specified minimum separation time between data pulses. For example, if the specified minimum separation time between data pulses is <NUM> msec, and if it takes about <NUM> msec for a data pulse to travel from one pod to the next, then, after a pod repeats a pulse, the pod will ignore any received pulses for the next <NUM> msec. In that way, each pod will repeat each set of data pulses only once. After a specified time-out period following the last repeated data pulse, each repeating pod will transition back into its sleep mode.

Since the vibrations and pressure changes associated with an event may be independently detectable at two or more different intermediate pods <NUM>, in order to avoid multiple, overlapping sequences of pulses corresponding to the same event, whenever an intermediate pod <NUM> is in its awake mode as a result of receiving a wake-up pulse, that pod will disable its own event-detection processing. In this way, the intermediate pod <NUM> that is "closest" to the event will initially be the only event-detecting pod. In some implementations, after an intermediate pod <NUM> is an event-detecting pod, it starts an internal timer that prevents the pod from again becoming an event-detecting pod for the duration of the timer. In this way, other intermediate pods <NUM> that are "farther away" from an event can become subsequent event-detecting pods for that same event. If different intermediate pods <NUM> happen to detect an event sufficiently close in time, they may both end up transmitting sequences of current pulses that interfere with one another. In that case, the transmitted data may be unintelligible, but the terminal pods <NUM> will still receive an indication that an event was detected.

In addition to or instead of being woken up based on the detection of an event, in some implementations, an intermediate pod <NUM> may be periodically woken up based on the pod's local clock signal. In that case, the pod may transmit a sequence of current pulses comprising a wake-up pulse followed eventually by a set of data pulses corresponding to the measurement signals generated by the pod's one or more active sensors, for example, to establish normal ambient conditions as a baseline for the detection of events and/or to track gradual changes in ambient conditions over time. Here, too, these pulses will result in the waking up of the other pods and the repetition of the data pulses for ultimate transmission to the terminal pods <NUM>. In some implementations, the periodic awakenings of the different pods are staggered in time in order to prevent pulses initiated by different pods from interfering with one another.

<FIG> is a schematic block diagram of an example of a pod <NUM> that can be used to implement each of the intermediate pods <NUM> of <FIG>, according to some implementations. As shown in <FIG>, the pod <NUM> includes a controller <NUM>, a battery <NUM>, a clock generator <NUM>, one or more passive detectors <NUM>, one or more active sensors <NUM>, a transmitter (TX) coil <NUM>, a receiver (RX) coil <NUM>, and a magnetic core <NUM>/<NUM>. <FIG> represents the electrical components <NUM>-<NUM> in block-diagram format, while showing a cross-sectional view of the TX and RX coils <NUM> and <NUM> and the magnetic core <NUM>/<NUM>.

As explained previously, the pod <NUM> may be implemented in two shaped portions <NUM> and <NUM>, each of which has a corresponding part <NUM> or <NUM> of the magnetic core <NUM>/<NUM>, where the TX and RX coils <NUM> and <NUM> surround the magnetic core part <NUM> of the pod portion <NUM>. Although not explicitly depicted in <FIG>, also located within the pod portion <NUM> are the electrical components <NUM>-<NUM>. Each pod portion <NUM> and <NUM> is individually encapsulated within a suitable (e.g., plastic) material to protect the pod's electrical components from corrosive materials, such as seawater. The inner space of each pod portion <NUM>/<NUM> may be filled with an appropriate dielectric liquid (e.g., oil) in which the electronics bathe. An interface (not shown), such as a flexible membrane or bellows, enables the internal and external pressures to be balanced.

The two pod portions <NUM> and <NUM> are joined together around the cable <NUM> using a suitable clamping mechanism (not shown in <FIG>) to configure the assembled pod <NUM> with the cable <NUM> passing through the resulting (e.g., cylindrical) opening in the pod. Note that, even though the two magnetic core parts <NUM> and <NUM> are not galvanically interconnected, they are inductively interconnected to enable a contiguous magnetic field to be formed around the cable <NUM>. Because the magnetic core <NUM>/<NUM> is inductively coupled, but not galvanically connected, to the cable <NUM>, each pod can be configured to the cable without having to modify the structure of the cable itself.

As explained previously, when a detectable event, such as an earthquake, a tsunami, or movement near the cable, occurs, a passive detector <NUM> causes the controller <NUM> to (i) transition from its sleep mode to its awake mode and (ii) optionally energize the one or more active sensors <NUM>, which would generate corresponding electrical measurement signals <NUM>. The controller <NUM> then energizes the TX coil <NUM> to inductively generate a wake-up pulse and subsequently an optional set of data pulses propagating along the cable <NUM> in both directions away from the pod. In particular, the electrical energy in the TX coil <NUM> inductively induces magnetic energy in the magnetic core <NUM>/<NUM>, which in turn induces electrical energy (i.e., current) in the cable <NUM>. By selectively varying the energy in the TX coil <NUM>, the controller <NUM> is able to generate, in the cable <NUM>, the wake-up pulse and the optional set of data pulses identifying the detected event and optionally characterizing the detected event with the associated measurement signals.

Similarly, when the controller <NUM> is awoken based on the local clock signal, the controller will energize the one or more active sensors <NUM> and then energize the TX coil <NUM> to inductively generate a wake-up pulse and subsequently a set of data pulses propagating along the cable <NUM> that identify and characterize the active sensor measurement signals.

Reciprocally, when a wake-up pulse propagating along the cable <NUM> arrives at the pod <NUM>, electrical energy is induced in the RX coil <NUM> via the magnetic core <NUM>/<NUM>, which electrical energy causes the controller <NUM> to transition from its sleep mode to its awake mode. The controller <NUM> then energizes the TX coil <NUM> to repeat the wake-up pulse via the magnetic core <NUM>/<NUM>. In a similar manner, when the subsequent data pulses arrive at the still-awake pod <NUM> and energize the RX coil <NUM>, the controller <NUM> responds to energize the TX coil <NUM> to repeat those data pulses.

Those skilled in the art will understand that the TX coil <NUM>, the magnetic core <NUM>/<NUM>, and the cable <NUM> function as a first transformer capable of transferring energy from the pod <NUM> into the cable <NUM>, while the RX coil <NUM>, the magnetic core <NUM>/<NUM>, and the cable <NUM> function as a second transformer capable of transferring energy from the cable <NUM> to the pod <NUM>, where the operating characteristics of each transformer depend, in part, on the number of turns around the magnetic core part <NUM> for the corresponding coil <NUM>/<NUM>.

In certain implementations, the magnetic core <NUM>/<NUM> is made of a suitable ferromagnetic material, such as a soft steel, with sufficient magnetic permeability (for example, > <NUM>) and sufficient dimensions to allow the transmission of sufficiently strong pulses from the pod to the cable.

In some implementations, the intermediate pods <NUM> of <FIG> function solely as passive event detectors. In those implementations, the one or more active sensors <NUM> and the clock generator <NUM> of <FIG> are optional. Note that, in those implementations, an event-detecting pod might transmit only the wake-up pulse as the sole indication of detection of an event. In some other implementations, the intermediate pods <NUM> function solely as ambient-condition monitors. In those implementations, the passive detectors <NUM> of <FIG> are optional. In these alternative implementations, each intermediate pod <NUM> would still be able to repeat received pulses. In some other implementations, some of the intermediate pods <NUM> of <FIG> function solely as repeaters of pulses received from other pods. In those implementations, the passive detectors <NUM> and the active sensors <NUM> of <FIG> are optional.

In some embodiments, since the terminal pods <NUM> do not need to be able to detect events, monitor ambient conditions, or repeat received current pulses, the design of each terminal pod can be a simplified version of the design of the pod <NUM> of <FIG>, where the passive detectors <NUM>, the active sensors <NUM>, and the TX coil <NUM> are optional. In addition, since the terminal pods <NUM> may be terrestrial and therefore externally powered, the battery <NUM> is optional. In some embodiments, one or both terminal pods <NUM> are able to transmit instructions to the intermediate pods <NUM>. In that case, such terminal pods <NUM> would have a TX coil <NUM>.

Although the disclosure has been described in the context of pods that transmit information using current pulses, in alternative embodiments, the pods could transmit information using any suitable type of electrical signals, such as (without limitation) a low-frequency voltage signal or a current wave.

Although the disclosure has been described in the context of pods having separate TX and RX coils, in alternative embodiments, a pod may have a single coil that can function as either a TX coil or an RX coil.

Although the disclosure has been described in the context of pods located along a submarine power-transmission cable, those skilled in the art will understand that embodiments of the disclosure can also be implemented in the context of other cables that have an electrical conductor spanning the length of the cable, whether or not that electrical conductor is used to carry an independent electrical current, such as (without limitation) a fiber-optic cable having an electrical conductor spanning the length of the cable in addition to one or more optical fibers. Furthermore, in some applications, the cables may be entirely terrestrial instead of partially submarine and configured to, for example, make scientific measurements and/or detect and monitor for terrestrial events.

The disclosure has been described in the context of cable-with-pods assemblies having a single cable <NUM> with two terminal pods <NUM>, where each terminal pod processes pulses from all of the intermediate pods <NUM>. In some other embodiments, each terminal pod <NUM> processes pulses from only a subset of the intermediate pods <NUM>. In some other embodiments, cable-with-pods assemblies might have only one terminal pod <NUM> that processes pulses from all of the intermediate pods <NUM>. In still other embodiments, cable-with-pods assemblies may have a meshed network comprising multiple intersecting cables, with (i) one or more intermediate pods on each network branch and (ii) a terminal pod at the terminal end of each branch that processes pulses from its branch pods.

Various modifications of the described embodiments, as well as other embodiments within the scope of the disclosure, which are apparent to persons skilled in the art to which the disclosure pertains are deemed to lie within the principle and scope of the disclosure, e.g., as expressed in the appended claims.

It will be further understood that various changes in the details, materials, and arrangements of the parts which have been described and illustrated in order to explain the nature of this disclosure may be made by those skilled in the art without departing from the scope of the disclosure, e.g., as expressed in the following claims.

Although the elements in the following method claims, if any, are recited in a particular sequence with corresponding labeling, unless the claim recitations otherwise imply a particular sequence for implementing some or all of those elements, those elements are not necessarily intended to be limited to being implemented in that particular sequence.

Also for purposes of this description, the terms "couple," "coupling," "coupled," "connect," "connecting," or "connected" refer to any manner known in the art or later developed in which energy is allowed to be transferred between two or more elements, and the interposition of one or more additional elements is contemplated, although not required. Conversely, the terms "directly coupled," "directly connected," etc., imply the absence of such additional elements.

The described embodiments are to be considered in all respects as only illustrative and not restrictive. In particular, the scope of the invention is defined by the appended claims rather than by the description and figures herein.

The functions of the various elements shown in the figures, including any functional blocks labeled as "processors" and/or "controllers," may be provided through the use of dedicated hardware as well as hardware capable of executing software in association with appropriate software. Moreover, explicit use of the term "processor" or "controller" should not be construed to refer exclusively to hardware capable of executing software, and may implicitly include, without limitation, digital signal processor (DSP) hardware, network processor, application specific integrated circuit (ASIC), field programmable gate array (FPGA), read only memory (ROM) for storing software, random access memory (RAM), and non-volatile storage.

In this specification including any claims, the term "each" may be used to refer to one or more specified characteristics of a plurality of previously recited elements or steps. When used with the open-ended term "comprising," the recitation of the term "each" does not exclude additional, unrecited elements or steps. Thus, it will be understood that an apparatus may have additional, unrecited elements and a method may have additional, unrecited steps, where the additional, unrecited elements or steps do not have the one or more specified characteristics.

It should be appreciated by those of ordinary skill in the art that any block diagrams herein represent conceptual views of illustrative circuitry embodying the principles of the disclosure.

As used herein and in the claims, the term "provide" with respect to an apparatus or with respect to a system, device, or component encompasses designing or fabricating the apparatus, system, device, or component; causing the apparatus, system, device, or component to be designed or fabricated; and/or obtaining the apparatus, system, device, or component by purchase, lease, rental, or other contractual arrangement.

Claim 1:
An apparatus comprising:
a cable (<NUM>) having an electrical conductor (<NUM>) spanning the length of the cable;
a pod (<NUM>) comprising at least two coils (<NUM>, <NUM>) and a controller (<NUM>), characterized in that the pod (<NUM>) further comprises a magnetic core (<NUM>,<NUM>), wherein:
the pod (<NUM>) is configured around the outside of the cable (<NUM>) such that the magnetic core (<NUM>, <NUM>) is around and inductively coupled to the electrical conductor (<NUM>) of the cable (<NUM>), wherein the magnetic core is not galvanically connected to the electrical conductor (<NUM>) of the cable (<NUM>), the at least two coils (<NUM>, <NUM>) being inductively coupled to the magnetic core (<NUM>, <NUM>), and the controller (<NUM>) being connected to the at least two coils (<NUM>, <NUM>);
the pod (<NUM>) is configured to transmit one or more outgoing electrical signals on the electrical conductor (<NUM>) of the cable (<NUM>) by the controller (<NUM>) electrically energizing a transmitter coil (<NUM>) of the at least two coils (<NUM>, <NUM>) such that outgoing magnetic energy is induced in the magnetic core (<NUM>, <NUM>) such that the one or more outgoing electrical signals are induced in the electrical conductor (<NUM>) of the cable (<NUM>);
the pod (<NUM>) is configured to repeat one or more incoming electrical signals on the electrical conductor (<NUM>) of the cable (<NUM>) by the one or more incoming electrical signals inducing incoming magnetic energy in the magnetic core (<NUM>, <NUM>) such that incoming electrical energy is induced in a receiver coil (<NUM>) of the at least two coils (<NUM>, <NUM>), wherein the controller (<NUM>) is configured to respond to the incoming electrical energy by electrically energizing the transmitter coil such that outgoing magnetic energy is induced in the magnetic core (<NUM>, <NUM>) such that the one or more incoming electrical signals are inductively repeated in the electrical conductor (<NUM>) of the cable (<NUM>),
wherein the transmitter coil (<NUM>) and the receiver coil (<NUM>) are two different coils.