GB2503310A - A transportable telecommunications cabinet providing digital subscriber line access and telephony - Google Patents

Abstract

A transportable telecommunications cabinet assembly mounted on a vehicle chassis, comprising: a first compartment (6) accommodating a digital subscriber line module (DSLAM) (100), a second compartment (10) for accommodating a copper cable connection point (103) for interconnection with the digital subscriber line module during use, and attachment means attaching the first compartment and the second compartment on the vehicle chassis. A third compartment (8), between the first two, may accommodate a power supply source (50). The cabinet may be Fibre to the Cabinet (FTTC), with the digital subscriber line provided over fibre optic cable (55).

Description

TELECOMMUNICATIONS CABINET

This invention relates to apparatus, systems and methods relating to a telecommunications cabinet for use in a Fibre to the Cabinet (FTTC) system, in particular, a mobile cabinet including a Digital Subscriber Access Multiplexer (DSLAM) for deployment in a disaster recovery scenario requiring telephony (voice) and data telecommunications services to be established or re-established to customers.

FTTC is a hybrid optical fibre/copper pair network architecture that uses legacy local copper access infrastructure and technologies, and newer optical fibre which is built as and when necessary. A FTTC system typically includes pairs of street cabinets which are deployed' in the access network at a location typically within a few hundreds of metres from a customer or user's premises. One cabinet serves as the Primary Cross-Connection Point (PCP) (shown in Figure 1A) which is usually a legacy item and connects copper telephone lines to the exchange. The second cabinet (shown in Figure 16), here also referred to as a Next Generation Access Network (NGA) cabinet, is usually a new build and houses the active electronic components needed to provide a fibre-based Digital Subscriber Line (DSL) data service to the customer served by the cabinet pair. Opticalfibre backhaul cables (on the network side) and copper end user connections (on the customer side) are led, usually through underground ducts, to the cabinet, where they are interconnected on DSL. electronics such as a OSLAM, a Multi-Service Access Node (MSAN) or the like, that receives signals from multiple customer DSL connections for onward transmission on an optical backbone using high-bandwidth copper technologies. The electronics typically run on mains power with batters, back-up. Tie cables connect the cabinet riair, which are usually located near to each other, typicallywithin lOm of each other.

A schematic representation of the DSLAM street cabinet (1) in the cabinet pairs of the.

prior art is given in Figure 1A. A DSLAM module (100) is connected (114) in the form of an optical link to the DSL backhaui leading eventually to the exchange. The DSLAM is powered by a power supply (51) which typically varies depending on the make, type and size of the DSLAM. The DSLAM service module (100) is connected to copper connection strips (102) using manufacturer-sUpplied plug-in connecterised cables.

(110), which are factory supplied permanently attached to the connection strips (102).

Connections in the form of tie cables (112) to and from the exchange and end users via the PCP cabinet are releasably (49) punched down on the strips (102). As shown, as many connection strips (102, 102') as are necessary are provided, in which a first strip would cater to connection of e.g. lines 1 to 150 of the OSLAM module, the second strip to lines 151 to 300, and soon. As a cross cOnnection or point, this arrangement allows ¶or fledbility (e.g. when a customer desires to switch from a voice-only Plain Old Telephone Service (POTS) to a FTTC DSL service) by allowing for the tie cable connection (112) to/from the network/customer to be removed and changed. Hence there is never any need for the connection between the DSLAM and the strips (110) to be changed.

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Figure 1 B depicts the other half of the well known prior art street cabinet pair, the PCP cabinet (40). FQr illustration, two interconnection strip or block pairs are shown, although as many block pairs are provided as needed to serve customers. The first block pair (42, 42') accommodate connections for voice services, while the second block pair (44, 44') accommodate connections to and from the DSLAM cabinet (1) by means of tie cables (112, 112'). Simplistically, DSL service is introduced to a voice-only line by re-running the jumpers (99) previously run between first block pair (42, 42') to the second DSLAM block pair (44, 44'). This routes the previous voice-only line through the OSLAM module (100) with the result that the output carries voice and IJSL data.

For historic reasons in the UK, different operatives have charge of each cabinet. Under normal circumstances, there is seldom any reason to access the DSLAM cabinet once the electronics have been provisioned, aside from the relatively rare occurrence of e.g. installing a further line card and associated DSL filters into DSLAM interconnection strips to serve customers above and beyond the already installed, capacity. The PCP cabinet, on the other hand, is likely to see more activity: for example when an end user customer commissions DSL service, requiring for the customer's end connection cable (jumper) to be re-routed within the PCP cabinet aè described above. 30,

As the name suggests, street cabinets are located near roads or streets, typically on the pavement or pedestrian walkway. Their visibility and proximity to passers-byand traffic makes them vulnerable to intentional or accidental damage. For example, up to 288 customers served by the DSLAM housed in the cabinet could lose voice and DSL services in the event of vandalism, a road acdident, flooding or fire. In situations where e.g. the concrete plinth upon which the cabinet sits and/or where the power supply is substantially damaged, the conventional disaster recovery response is to replace the cabinet. In addition to the reprovisioning of the cabinet itself and its connections, the plinth will have to be rebuilt, and the power supply will have to be removed and replaced: the work in itself would take a few days. In practice, the need to coordinate the schedules and activities of fibre and copper engineers, and external suppliers such as power companies and civil engiheer operatives, means that restoration of.DSL connections may take weeks or even months. Until such time, service to end users and Internet Service Providers is disrupted. *1o

It would be desirable to provide a speedy and flexible disaster recovery solution at any time under any conditions in the event of damage to a street cabinet, which can be set up quickly and easily to minimise the time and disruption to customers and residents in the thea, in terms of restoring their service as well as the physical inconvenience caused from repair activities.

According to a first aspect of the invention, there is provided a vehicle including a telecommunications cabinet assembly comprising -a first compartment for accommodating a digital subscriber line module, -a sedond bompartment for accommodating a copper cable flexibility point for interconnection with the digital subscriber line module during use, and -a vehicle chassis attaching the first compartment and the second compartment within the cabinet assembly.

The, cabinet assembly comprises separated compartments or housings which contain the components necessary to provision a DSL connection to customers. The respective compartments are attached, directly or indirectly, to each other within the assembly by the chassis or similar subframe or framework of the vehicle, so that the pair of compartments can function as e.g. a single FTTC unit, and can be transported as such. An onboard power source is preferably included in the mobile cabinet assembly in a third compartment.

Preferably, the cabinet assembly takes the form of a trailer which may be towed, although it can as advantageously take the form of any other unpowered or powered vehicle. The compartments could be secured by bolting or screwing them directly to each other, to form a contiguous, unitary structure, or one wherein the compartments are fixedly distanced from each other. The compartments in the embodiments * discussed are separate from each other, so that the components in each compartment are not accessible from another compartment. This has the advantage securing away those compartments which will not need to be accessed in the field; for example, there is typically no need to reconfigure the DSLAM unit in the electronics compartment at the disaster site, as will be explained below. However, it would be realised by the skilled person that it is not essential to completely isolate the components of each compartment, ard indeed it might be possible to locate all the components in compartments which are open to each other i.e. with little or no wall structures between, them.

In the embodiment of the invention discussed, the third compartment containing the onboard power source is located in the middle of the assembly and so éeparates the DSL and copper flexibility compartments from each other, for reasons whic,h will be explained below. The cabinet assembly can be powered from any suitable power source, such as mains power or by a generator, so a power supply source separate from the cabinet assembly (e.g. a separate generator) can be used. In preferred embodiments however, the cabinet assembly carries its own po'.er supply, which advantageously provides an all-in-one disaster recovery solution. The third compartment tiouses banks of batteries, which is preferred owing to their being quiet in use. Power is drawn from each battery bank in turn in a way so that when voltage levels of the operational battery bank falls below a certain predetermined level, another battery bank on standby takes over the supply of power before the first battery bank winds down its output. It would be possible for a power generator or the like to be housed in the power supply compartment as an alternative to using batteries of any type of configuration, which would still realise the advantage of providing a self-* contained DSL disaster recovery solution; In further preferred implementations, a messaging system is included, which gives the trailer cabinet assembly the capacity to send and receive meséages. Preferably the messages are sent wirelssly, and can take theform of Shod Message Service (SMS) text messages, or automated voice calls. A further preferred inclusion is a control unit in the form of e.g. processor, which serves to monitor and control the operation of the banks of batteries,* as well as to reply to queries, and generate status updates, alerts and alarms upon the occurrence of redefined events such as unauthorised door opens, excessively high temperate in the battery compartment, and so on.

In other embodiments of the invention, the DSLAM interconnecticui strips or block in the first, DSL, compartment are permanently interconnected using a tie cable to the terminal block in the second, copper interconnections compartment. In a preferred implemntation, an insulatipn displadernent connection (IDC) termination is provided on the first, permanent, side of the DSL terminal strip. As will be described further below, conventional practice is that such terminal strips are typically permanently connected to the DLSAM module, and releasably conn!cted to the copper flexibility interconnection * block. By reversing this practice, the tie cable connection between the DSLAM terminal block and the copper flexibility interconnection strip within the cabinet assembly is made persistent. This obviates any need for changes to be made between the two compartments even if changes are made elsewhere within the cabinet 15' assembly. This is of particular use when e.g. it is necessary to change out the DSLAM module to enable the cabinet assembly to serve as a replacement: for a destroyed street cabinet. . , While the apparatus and the methdds of the invention are particularly suitable for use in the context of a mobile cabinet, assembly, it would be appreciated that the persistent, durable, connections made can be used in within a static cabinet arrangement, such as in conventional street cabinets, e.g. during equipment replacements or upgrades.

The desired result can be obtained by simply placing the DSLAM terminal strips baqk to front from their usual orientation within the electronics compartment. In preferred implementation, the second, releasable, side of the. strip faces the DSLAM unit. The skilled person would however appreciate that the same effect can be obtained using longer DSLAM and tie cables which would reach the respective sides, regardless of the * exact position and configuration of the DSLAM terminal strip.

30' * - * The' cabinet assembly is also configured to allow for DLSAM swap outs, as will be explained below: to this end,, the OSLAM units are releaably connected to their * terminal strips, while the interconnection between the DLSAM terminal strips and the interconnections blocks in the copper flexibility compartment are made permanent. - * * * --* * . * * In Use, the trailer cabinet assembly is arranged to be used with cable ducting which safely conveys cables to and from a footway box via cable pods in the floor of the copper cable flexibility compartment and a modified footway box cover.

According to a second aspect of the invention, there is provided a method of providing a digital subscriber line service comprising * -transporting, a vehicle including a telecommunications cabinet assembly of the invention to a site, * -at the site, bringing a telecommunications cable from outside the telecommunications cabinet assembly into the second compartment, and -connecting the telecommunications cable to copper cable flexibility point.

As will be described below: embodiments of the telecommunications' cabinet assembly * of.the invention allow for customer to be provided with a DSL service by providing connections to be made by bringing a cable into the copper compartment of the cabinet assembly and connecting it to the flexibility point.

In further implementations, the persistent tie cable arrangement between the DSLAM and copper flexibility terminal strips or blocks in place permits the reprovisioning of the cabinet assembly as a replacement for a variety of DSLAM types, by swapping out the current DLSAM module quickly and easily. The DSLAM cable is removed from its impermanent connection to the terminal strip, the module removed, and replaced with the desired DSLAM type, and the connections'rernade with a DSLAM cable appropriate to the replacement DSLAM unit Of course, if the DSLAM cable is the sam'e as the previoUs module (and if it can be disconnected at the end into which it connects to the DSLAM unit), there is no need to provision a second cable'if the existing cable can be used. In the event that the DSLAM bracket currently attached to the interior of the electronics compartment is the wrong size, this can be unbolted or unscrewed: and one of the correct dimensions be,fixed in its place, to which the replacement DSLAM * module is fixed.

Advantageously, no further cabling or changes need be made within the cabinet assembly after the new DSLAM unit is installed. * . Systems, methods and apparatus embodying' the present', invention' will now be described by way of example only, with reference to the following drawings, wherein: Figures 1 A and lB are schematic drawings. of an FTTC street cabinet pair of the prior ad; Figures 2 and 3 are external views of a trailer cabinet assembly; Figure 4 is a block diagram of the parts of the trailer cabinet assembly; Figure 5 is a view of the interconnection compartment; Figure 6 depicts the power supply compartment; , Figure 7 is a detailed view of the power suØply units;.

Figures 8A and SB show the format of messages sent to and from the trailer cabinet assembly; Figure 9 depicts the messaging and alarm operations of the trailer cabinet assembly; and Figures 10 and 11 show views of ducting which leads cable between the underground network and the trailer cabinet assembly.

A schematic representation of an exemplary embodiment of a cabinet asembly (2) according-to the inyention is depicted in Figures 2 and 3. These exterior views show the cabinet assembly mounted on wheels (4) and prQvided with support wheels1 legs or stability jacks (20 in Figure 3, 19 in Figure 11)which can optionally be wound down or folded out to engage with the ground when the trailer is not travelling. The cabinet assembly comprises a weatherproof (e.g. powder coated steel) housing or enclosure, and includes a foldable (ow bar (for further security) (12) allowing for the cabinet * assembly (2) to be hitched to a suitable truck or van for towing to the disaster recovery * 25 site. A loàkable cover (22, Figure 3) is provided for use when the tow bar is moved to its upright, storage, position. For the purposes of this specification, the end of the cabinet assembly at which the tow bar is provided, is referred to as the forward" or "front" end, while the opposite end is the "back" or "rear" end. . . In a preferred embodiment, the trailer is configured to auto-brake when the towing vehicle slows, and includes vehicle suspension, appropriate lights (e.g. sidelights, indicators, reverse and fog lamps), its own handbrake, and wheel locks. In one.

implementation, the ciabinet assembly is mounted on a two-wheeled trailer chassis on a 1500 kg axle. Security features in the form of movement and vibration sensors (32, 34 in Figure 9) and tracking and locational devices can also be provided for use especially in the.event of unauthorised movements of the trailer Cabinet assembly compartments As shown in Figures 2, 3 and 4, the cabinet assembly comprises three substantially rectangular enclosures serving as compartments which house* respectively (i) the active electronics required to provision a DSL service, (U) the power supply units in the form of e.g. banks of batteries, and (iii) interconnection means for fibre and copper cables. The electronics compartment (6) is located at the front end of the cabinet assembly, the interconnections compartment (10) is placed at the back end of the cabinet assembly, and the power supply compartment (8) is positioned in the centre, separating the front and back compartments. The compartments are fixed in their positions within the cabinet assembly; by being bolted or otherwise attached or fixed to the subframe or chassis of the trailer. This enables the compartments to be transported or moved as a single unitto and from the disaster recovery site.

Figure 4 is a schematic view of the components, modules, and functionalities of the three cabinet compartments (here depicted in a contiguous arrangement) making up an exemplary embodiment of the invention. . The front compartment (6) of the cabinet asernbly seives to accommodate active electronics, and is a 1200 mm x 1200 mm x 400 mm (HxWxD) enclosure. In use, it contains the OSLAM unit (100) which typically comprises the same or similar DSLAM components deployed in a street.cabinet, such as. electronics cards. The DSLAM module is mounted on a bracket (68), which varies according to the particular model and make of the DSLAM. The electronics compartment further includes components to provide and manage the onboard power, viz, a battery management control module and associated chargers. In one implementation, the electronics compartment could contain a VDSI_ DSLAM, interconnecting terminal strips (102) (also referred herein as "JPX strips" when supplied by Huawei Technologies Co. Ltd with their OSLAM modules described below), and associated splitterslfilters. the OSLAM is releasably connected to the terminal strips as will be described below. It plugs into the power socket (57), and is connected to the fibre splice module (105) via fibre link (24). The electronics compartment also includes the processors and electronic required for onboard battery management, cooling, and operation of the alarm and messaging systems. Preferably, 9.

the control modules are configurd so that the DSLAM and the other electronics can be controlled independently of each other. The chamber of this compartment can be accessed via doors (14) which are hinged to open laterally from a centre line, and face forwardly in the direction of the tow bar. The doors are also supplied with locks (16), and in a preferred embodiment are fitted with alarms (18) for even greater security.

Access tO the electronics compartment is not typically needed once the DSLAM is active at the disaster site, so the electronics are by design located Separately from the interconnects compartment. The electronics compartment doors are further secured by being placed behind the foldable tow bar which áerves as a further, physical, impediment against unwanted interference, as shown in Figures 3 and 6. The doors are preferably configured so that each time they are opened, an alert in the form of e.g. an SMS message is generated and sent to a remote monitoring station. A further local audible/visible alarm can also be set off if it is thought that the door opening event is unauthorised.

The interconnections compartment (10) is housed in an enclosure simila.r in dimension and materials to the front compartment, and is placed at the back end of the cabinet assembly with its doors (15, in Figure S) facing rearwardly. It contains the cable connector storage and terminating areas, allowing the compartriient to serve as a PCP for interconnections to be made between an optical fibre of the network and a copper wireof the end customer. In a preferred embodiment1 the compartment is arranged so that it resembles -the interconnection portion o a street cabinet, usefully presenting a familiar interface to the operatives who have charge of conventional PCP cabinets.

Even the door key used could be of the type used for street cabinets.

An exemplary configuration for use in the UK by British Telecommunications plc (BT plc) could include a punchdown or DC terminal blocks (103) (e.g. QuanteTM strips manufactured by the 3M Company) for copper in/out cables to be punched down on, and, a splicing module (105) for optical fibre, as depicted.in Figure 4. The chamber of this compartment can be accessed from the back of the cabinet assembly via doors similar to those of the front electronics compartment, ani are also provided with locks (16), alarms (18) and is capable of sending alerts whenever they are opened.

The interconnection compartment further includes cable ports (not shown) in its floor to enable signal cables to pass between the cabinet assembly and the underground cable network via the footway box (56, Figure 10), preferably being securely guided through flexible ducting (26). The ports take the form of two circular holes of e.g. 100 mm diameter; and in use the cables pass through corresponding cable ports in a modified footway box cover (28) from the underground network to the trailer cabinet assembly as shown in Figure 10. Stoppers or bungs (30) are provided to seal the ports in the compartment and the footway box lid respectively, when they are not in use. As will be discussed further below, an alarm (31) is also provided to generate an alert when the ports or the cables passing through are tampered with. 10.

There is typically no need for access to the active electronics during the disaster recovery operation at the disaster site: Segregating the electronics and interconnects into separate enclosures isolates the vulnerable, electronic components from unintended interference. However, physical separation is not essential to the operation of the trailer cabinet assembly, and the advantage of protecting the electronics from undue harm can be realised in different ways, e.g. by employing operatives with

expertise in both fields. .

Referring now to Figures 4, 6 and 7, the central compartment or chamber (8) houses the power supply for the cabinet assembly, and is located to physically separate the front and back sub-chambers (6, 10 respectively). In the embodiment shown in the drawings, the power supply compartment (8) is positioned lengthways between the two other compartments. The skilled person would however appreciate that the relative positions of the subchambers are not essential to the operation of the cabinet assembly as a whole. Also, any desired separation of functions may be achieved in otherways, e.g. by logical rather than Øure physical separation. The power supply compartment includes a çair of gull wing doors. on each side along its length (17, see also Figure 6 for the doors in an open position) which can be opened upwardly on each.

side and held open with gas struts (52, Figure 7), which gives unimpeded access to the chamber within. As with the doors of the other compartments, they are fitted with locks and alarms (16, 18). Further seCurity can be hSd in the form of securing bars over each battery bank, which would also help keep them in place during transportation of the trailer cabinet assembly. . . As will be explained in greater detail below, the chamber of this compartment is configured to accommodate a number of banks of batteries (50). To deal with the heat generated during operation, the housing of this compartment is provided with louvers or other entilation ports as well as a cooling fan in preterred embodiments. An onboard smoke alarm (36) capable of generating an alert can also be included.

The trailer cabinet assembly is intended to serve as a sell-contained, complete, replacement for a destroyed street cabinet which may be swiftly brought to the site to enable reconnection of DSL service to customers within hours. It is designed to provide customers with a temporary service until the original street cabinet can be restored or rebuilt, but it could well serve as a pernianent replacement cabinet. The cabinet assembly is not limited to purely replacement functions: it could also be deployed on an ad hoc basis where a connection may be required quickly, or for a limited period, at the site (assuming that the necessary copper and/or fibre cables on the network and customer sides are available or can be brought to the trailer cabinet assembly).

Cabinet assembly cabling Referring generally to Figure 4, copper connections (53, 53') from outside the trailer cabinet assembly are made to the DSLAM (IQO) in the electronics bompartment (6) via mounting blocks (103, 103') in the interconnection compartment, and terminal strips (102, lO2J) by means of tie Cables (24). As can be seen in Figure 1, the tie cables are * led through holes in the respective bulkheads of the front and rear compartments on cable trays (21) extending the length of the power supply compartment (8). The external fibre connection (5) is led to/from the DSLAM directly from the fibre splice unit (105), which cable is also led between the electronics and interconnects compartments via the power compartment. Power is fed in to the electronics compartment from the power supply units (50), allowing for the provision of a power socket (57) into which the DSLAM and other electronics can be plugged into.

As will be elaborated below, the trailer cabinet assembly is configured so that it can be re-commissioned for use with another DSLAM type. To this end, the DSLAM unit (100) is detachably provided within the electronics compartment, and can b! removed or* unbolted from its mountings (68) and disconnected from the terminal strips (102), power supply, and optical link. In use, the terminal strips (and their associated -12 mounting blocks) are a permanent feature of the trailer cabinet assembly and are permanently connected to the connection strips in the interconnect compartment (10).

This forms a permanent connect path between the electronics compartment (6) and the interconnections compartment (10) for both copper and fibre cables (63, 65 respectively). These connections do not need to be altered for the life of the trailer cabinet assembly, so in normal. circumstances the only part of the trailer cabinet assembly which will be accessed at the disaster site is the interconnect compartment.

More rarely, access will be required to the electronics compartment when a DLSAM change out is needed; which will now be described.

DSLAM change outs It is the current practice in the UK to provide a like-for-like replacement of the damaged DSLAM type owing to configuration and other issues. Where this is required, the trailer cabinet assembly is advantageously configured to be.daptabIe to operate with a variety of DSI,.AM types as will be described below. This increases the flexibility of using any available trailer cabinet assembly for any damaged DSLAM type, and reduces the number of trailer cabinet assemblies that might otherwise have been required. . 20. . -The exemplary cabinet assembly discussed here describes a wiring or cabling configuration suitable for use in the UK by BT plc. In the interconnections compartment (10) at the back end, a PCP-type interconnection can be obtained using "punch down' IDC strips or blocks (103) on the copper side (i.e. by cutting through the insulation sheath of the cable to effect contact with the metal within the cable), and a fibre termination unit e.g. a splice component (105) on the fibre.side. The active electronics compartmeht (6) at the front end contains e.g. a. stripped down version of a 288 line VDSL, OSLAM (manufactured by Huawei), with its Own interconnection strips (102) and.

associated splitters and filters. Other DSLAM types usetby BT plc include a 96 line DSLAM also from I-Iuawei, as well as models by other manufacturers such as ECI Telecom Ltd. DSLAM types typically vary between manufacturers and even between modpls' from the same manufacturer e.g. in terms of wiring configurations and backplane mounting brackets size. For example, the Huwaei DSLAMs mount into a 19" (48 cm) bracketor frame, while the ECI model fits into an ETSI tandard 21" (53 -35. cm)frame. . . , .. . In an implementation of the invention, the trailer cabinet assembly is factory-provisioned with a DSLAM module (e.g. the Huawei 288 line VDSL DSLAM mentioned above) in the electronic compartment (6) from Day 1. This allows for the DSLAM to be pre-connected to an appropriate head end; allowing for configuration data to be downloaded before deployment, so that the cabinet assembly is ready for immediate use for the disaster recovery of a damaged DSLAM of the same type. Advantageously however, the trailer cabinet assembly isnot limited to use only with the pre-specified DSLAM model, but can be subsequently swapped out in a modular fashion, to substitute damaged street cabinet DSLAMs of various types and models. So for example, if a Huwaei 288 line unit in a street cabinet needs replacing and no trailer cabinet assembly with a DSLAM of this type is available, a trailer cabinet assembly factory-fitted with a ECI line module can be deployed instead, after re-commissioning the current DSLAM onboard the trailer with the required model.

Preferabiy, the change out inthe electronics compartment is performed at a safe location e.g. at the trailer depot, although it is possible to perform this anywhere else e.g. where the DSLAM modules are stored, or at the disaster site itself. The process * involves changing the DSLAM module itself, th assoéiated ca6ling to the terminal strips (102) (which vary between DSLAM types) and, where required, its associated mounting kit. The current DSLAM module is disconnected from the optical connection (65) and the power supply (57). The DSLAM cabling (63) is also disconnected from the intercOnnect 6SLAM terminal strips at the terminal strip end (58). This is possible because, unlike conventional arrangements in street cabinets where this connection is permanent (owing to the cable being punched down in' the bC" interface), the cable (63) is temporarily or releasably connected to the DSLAM terminal strip. A special terminal strip can be designed and used for this purpose, but a simpler solution is to simply turn a known e.g. DSLAM terminal strip around and to use it in a reverse configuration to that intended by the manufacturer. The IDC interface on the DLSAM terminal strip (102) which effects punched-down connections, is in this way forms a permanent interconnection with the copper interconnections block (103), while the reverse side of the DLSAM strip is used to obtain a temporary, detachable, connection (56) to/from the DSLAM module (100). For contrast, it can be seen how, in Figure 1A, the prior art, conventional, method of using the terminal strip involves permanent connections being made with the DLAM using the IDC side of the terminal strip, while the releasable bonnection (49) is provided on the reverse "side of the terminal strip away from the DSLAM (100).

If the current mounting bracket (68) is not suitable for use with the new DSLAM unit, the bracket is also removed, and replaced with one of the correct dimensions, to which the new DSLAM is fixed. For convenienoe, all the sizes of brackets required for all the DSLAM types in the access network are carried on the trailer cabinet assembly. In the case of BT plc, two bracket sizes (19" and 21") wciuld allow fitting of all the DSLAM types deployed in street cabinets in the UK. The necessary power, optical and copper connections to the new DSLAM are then made. This involves reconnecting the fibre optical patch lead (65) leading from the fibre splice unit to the DSLAM, the power cable appropriate to the DSLAM with any necessary adapters (57), as well as the terminal strip cables (63) with the copper terminal strips (102). In respect of the terminal strip connections, cables specific to the DSLAM type are required, and because wiring configurations are different between different DSLAM types, wiring diagrams are provided in the form of a lookup or c?nversion chart, which will allow the formation of the correct connections between the DSLAM and the terminal strip. The cables are individually marked (using e.g. collets bearing reference numbers) allowing for the connections to be easily and accurately re-made with the trailer cabinet DSLAM.

This arrangement removes the need to also change the terminal strips and tie cables during a DSLAM change out, thus reducing the complexity and work needed: for example, the applicants have found that a DSLAM swap out takes only about an hours Power sup,bIy Referring now to Figure 6, the central compartment (8) of the trailer cabinet assembly * (2) contains the onboard power supply units whih enable the cabinet assembly to operate as a self-contained disaster recovery solution. As shown in e.g. Figure 4, the power is taken from the battery compartment (8) to the electronics compartment (6) to a socket (57), which allows for a variety of makes and types of DSLAM modules to plug into, either directly or via a suitable adapter.

In the example described here, the power supply takes the form of six banks of batteries (50) arranged in rows. The banks operate independently of each other, and each comprises four 12v batteries connected to the others within the bank toprovide the required 48v supply to power the DSLAM and other electronics. Preferally, each battery bank is arranged to meet a maximum demand requirement of 800W for a period of at least 4 hours so that the trailer cabinet assembly is capable of operating for more than 24 hours at maximum capacity without recharging or battery swap out.

Each bank is connected to the load with a diode, and during operation, ,power is drawn from a single battery bank at a time. The six banks are configured to auto-switch between banks by use of a control unit e.g. in the form of a processor, which monitors, the voltage of the bank in use. When the voltage of the bank in use falls below a predefined threshold, another bank is automatically activated to take over the supply of power. The events of voltage dropping below the threshold and/or the power supply handover are preferably marked by the sending of an alert to a remote, monitoring station (as will be described further below). After a predefined delay, the spent battery bank is deactivated and disconnected from the load. This serial, overlapping, handover process ensures an uninterrupted power supply to the cabinet assembly electronics.

In the described implementation, a battery status indicator is provided preferably in the form of a tricolour LEO associated with each bank of batteries, which preferably are vi&ble in daylight conditions: The following are examples of status indications: * Steady Green fully charged ready for use * Steady Red discharged ready for change out * Flashing Green or Red, being charged * Flashing Orange -in use DO NOT DISCONNECT Depleted battery banks can be recharged within the cabinet assembly itself, or be swapped out for a fresh bank of batteries and recharged away from the battery compartment, e.g. at a charging station, the trailer cabinet assembly storage depot, a local exchange or the like. Where the batteries are not to be moved from their location within the battery compartment, two built-in independent 1000W intelligent battery chargers are provided, which are capable of identifying which battery banks are depleted (which need charging), and which bank in use and connected to the load (to be avoided for charging). When activated, the rechargers will automatically trickle-charge a spent battery bank and sequentially move on to charge the next spent bank in turn. -Where battery banks are removed for charging, covers are provided to shroud potentially live battery connections. A remote battery charging module suitable for either van mounting or using in a workshop could comprise two béttery bahks of four batteries each, and two battery chargers identical to those used within the trailer. The exemplary charger nodule described here operates from 240v 13 amp supplies.

In addition or as an alternative to operating off battery power, the trailer cabinet assembly is configured to also accept power from eg. a 11 Ov AC generator. While this is an option available at the disaster recovery site, it is envisaged that this would tie used especially when the trailer cabinet is parked at its home exchange or storage depot. This is because of the level of disruption which would be caused to passing foot and vehicular traffic and residents in the area who would be affected by its presence and the noise generated. Its prohiinence could also attract unwanted attention from vandals. Hence a generator will be used only if the conditions are suitable or in an emergency (e.g. where the batteries are running dangerously low on power). * 20

* The generator can alternatively or additionally serve to recharge the battery banks in situ, for which a switch is provided to aVow selection of the recharging power source.

the skilled person would appreciate that it i also possible tb include a generator onboard the trailer cabinet assembly within the power compartment (8) for self- -contained (if slightly noisier) operation, in place of batteries.

Messaging Figure 9 depicts parts of the trailer cabinet assembly which can be monitored and/or alarmed, which status is monitored by the control unit. In the event of a detected status change or abnormality, an alert is triggered and transmitted by SMS via the antennas (25) to a central control centre. * . The exemplary trailer catnet assembly described here includes one or more onboard messaging systems. One possible-system can be set up to monitor the Io6ation of the trailer cabinet assembly and tracking functions (29), while another (27) monitors various aspects of the cabinet assembly as described further below. Wireless transmissions can be obtained via the antennas (25). The systems allow a remote monitoring or control centre to communicate with the cabinet assembly by sending instructions anJ interrogations, and by receiving alarms, alerts and updates. Preferably * the messages take the form of SMS messages which can be sent or received by a mobile telephone or other suitable receiving device at the central control centre.

Prior to deployment in the field at the disaster site, the control unit is set up for messaging using a suitable software program. The syntax for the messages is preferably pre-determined but modifiable as and when required. An example of a* message layout suitable to alert the central control station that the power supply compartment is too high (i.e. higher than a predefined temperature) is shown in Figure 8A, irom which it can be seen that details are provided as to which trailer cabinet assembly.is sending the message ("DRi Trailer"), the time and date of the event and/or message, and the subject mailer of the message ("Temperature too high").

Figure 8B depicts the format of a pair of interrogation and reply messages in which the trailer cabinet assembly provides information about which battery bank is in use: the outgoing message from the control tation is sent to trailer cabinet assembly's telephone number and contains a query about the front door (i.e. of the electronics compartment), which prompts the response from the compartment that its front door is closed ("frontdoorO").

Use of such pre-formatted messages allows for communication with the cabinet assembly control unit, and usefully enables remote monitoring. Othe! message types could include: -- * Event alerts and status updates from the trailer cabinet assembly * High temperature (13) * Bank of batteries changed out(11) *. Front door open (18) * Battery doors open (18) * Back doors open (18) * Smoke alarm (36) * Cable alarm (31) * Battery banks low warning (11) InterrOgation and reply messages * Which battery bank is in use? (11) * Is the battery door open?(18) - * Is the front door open? (18) - * Is the back.door open? (18) * How many banks of batteries are available for use? (11) Instructions to the cabinet assembly * Activate / deactivate the tracking device (32, 34) * Activate / deactivate alarms * Activate video cameras and other surveillance equipment Further and more complex message types and instructions may be used, depending on the processor or control unit of the cabinet assembly. The skilled person would appreciate that the message is not restricted to any particular format or that it must take the form of an SMS message: Attordinary vàice call can be placed by the trailer.

cabinet assembly to alert the central station of an unauthorised access, for example.

Alarms.

As noted earlier, the potentially vulnerable parts of the cabinet assembly such as the doors and tie cable continuity are monitored for unauthorised interference and activity.

Inaddition to status updates and alerts sent bymessaging a remote monitoring station, local alarms which are audible and/or visible are also deployed. In exemplary implementations, the alarm system can be deactivated prior to accessing the cabinet asserhbly, or else it can be deactivated within a given time after access, in the known manner. . . . The following are further examplesof eventsfor which an alarm maybe set off: -* Unexpected status changes, e.g. power on/off--this may indicate unauthorised is.

tampering with the cabinet assembly.

* Smoke and heat alarms (36) -this is deployed in the power supply compartment in particular.

* Unexpected movement e.g. vibration, tow away (32, 34) --unexpected incidences may be indicative of unauthorised activity, and the alarm (which is povered from the onboard power supply) is preferably kept activated when the trailer is stationery (i.e. at the disaster recovery site or during storage), and turned off only when it is being towed.

* Overspeed detection --the system will raise an alarm if/when trailer cabinet assembly travel speed exceeds a predetermined speed limit when being towed.

The skilled person would appreciate that further alarm features can be included, such* as the activation of audio and/or video recording devices when an event capable of setting off an alarm is detected.

Cable feed-in As shown in Figures 10 and 11, copper and optical cables (53, 55 respectively)from the underground network are brought to and from the trailer cabinet assembly via a footway box (56). The cables can if absolutely necessary be led into the interconnects compartment bare of any protection on a very short term basis, but much more preferably they are more securely guided using ducting (26) which is a flexible "umbilical cord" tube. This protects the cables from intentional or accidental damage, and by maintaining a gas and water seal, protects the interconnects compartment and footway box interiors The ducting is preferably further configured to ensure that the minimum bend radius of the optical fibre cables is respected. This could for example, take the form of corrugations on the ducting conduit tube which prevent overbending beyond a predefined extent (depending on the type of the optical fibre cable). The ducting is in any case formed from a strong flexible material, such as metallised tubing. As will be detailed belpw, the ductfrig is fitted into a modified footway box cover or lid (28) at one of its ends, and through the floor of the trailer cabinet assembly (specifically, that of the interconnections compartment) at the other end.

The footway box lid (28) is modifiea from a conventional Junction UndergroUnd Footway (JUF) lid in that it includes access holes allowing cables to pass to and from the trailer cable. At one end, the ducting is secured onto spigots provided on the lid access holes. The other end of the ducting is secured to the mouth of the cable port (24) through the floor of the cables pass into the interconnections compartment (10).

Where thelid access holes or cabinet cable ports areriot used, they are preferably stopped up with a bung or seal.(30). As noted earlier, the cable itself within the ducting is preferably monitored and alarmed, e.g. by incorporation of a sensor connected to a known pair within the tie cable(s) which when broken raises an alert. A disconnection triggers the SMS messaging system and/or the alarm system, allowing for unexpected -or unauthorised interference to be detected.

Figure 10 shows the back of the trailer cabinet assembly (2), specifically part of the doors to the interconnections compartment (10). The ducting (26) is shown extending between the cabinet assembly and the footway box lid (28). The footway box lid has been pulled out of position over the footway box (54) by an operative pulling on the lid handle (60) or grabbing means, allowing for access to the footway box to locate and work with the required cables from the underground network. Figure 11 shows the trailer cabinet assembly in its operational position positioned over the footway box.

covered by. the modified lid, after the underground cables have been led into the interconnections compartment.

During use, the arriving trailer cabinet assembly will typically be initially moved to a position over the footway box to bring the borresponding lid access holes and cabinet cable ports into proximity with each other. The ducting is fitted at each of its ends. The trailer cabinet assembly is then temporarily moved a small distance away (as shown in Figure 10), sufficient to allow the operatives access to the footway box, while the ducting connection remains in place. A certain length of slack ducting and cable needs to be provided to allow the trailer cabinet assembly to move the short distance away while remaining connected to the f otway box lid. This is necessary to allow access to the footway box as shown in Figure 10, and also to ensure that the cables within the interconnection compartment are not pulled out of position from the QuanteTM strips and splice box.

Database generation/restore process When a street cabinet suffers damage, the likelihood is that the records of the damaged or destroyed DSLAM will also be affected to at least some extent This part of the process seeks to replicate a "mirror' or to or regenerate these DSLAM records.

Three exemplary restore scenarios, relying on the availability of an uncorrupted config" (configuration) file, are: * Restore direct from an uncorrupted Super Control Unit Board (SCUB A SCUB card on the DSLAM processor/controller board holds the unique configuration data for a given DSLAM card. Typically two SCUB cards are used per DSLAM: a master card which stores the database information and a backup slave card. Where the SCUB card from the original.DSLAM of the damaged cabinet js still usable, data restore is a simple operation as all the configuration data needed to replicate the operations of the original DSLAM is contained on that card.

In such a case, the operative installs the original SCUB card into trailer cabinet assembly DSLAM, so that on boot up, the operations of the trailer cabinet assembly* -OSLAM fully replicate the original.

Restore-of saved con fig file via direct input from laptop or local PC If an uncorrupted SCUB card is not available (e.g. it has been physically damaged and/or the data on that board is unrecoverable), then it may be possible to restore the original configuration via a saved copy if available. Such a copy can be available from a peviously saved database copy on e.g. on a laptop computer. In this scenario, a new SCUB card is installed and the configuraticn data downloaded from the local PC.

* Restore con fig. file via Element Management System (EMS) In this worst case" scenario, where there is no usable SCUB card or back up copy available. In such circumstances, a SCUB card has to be commissioned "as new" and all data ever downloaded to the original DSLAM has to be "replayed" by contacting all the sub-systems which originally requested events through the remote EMS to replay those events either in a bulk load or as individual events.

Examples of such "events" are áhanging the data rate on a specific customer, installation of new customers, disconnection of old customers, and the like.

When the required database configuration files are recovered, connections between customers and the exchange èan be restored to restore DSL and other services in the usual way, by connecting customer cables on the IDC or copper mounting blocks.

Summary of deployment

The following is an example of processes involved in deploying a trailer cabinet assembly of the invention. - 1. A disaster, recovery event is reported to a central control station: th!s could originate from affected customers who have lost their DSL service; via alarm&reported by a central control unit, or else from the local authorities in the event of a traffic accident. The report would include information about the location of, and the DSLAM type and model' used in, the damaged cabinet. Instructions are sent to a trailer cabinet assembly depot (which may be co-located at a local exchange) to send out a recovery trailer cabinet assembly. A trailer cabinet assembly with the correct DSLAM module is identified if available, otherwise a trailer cabinet assembly with another DSLAM type is reconfigured by changing out the DSLAM to the correct type. The trailer cabinet assembly is hitched to a suitable truck or van and towed to the disaster site with * associated trailer cabinet assembly kit such as auxiliary charging unit(s), spare batteries and an interconnect kit to footway box. * . -

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2. At the site, any significant debris should have been cleared by the time the cabinet assembly arrives. Ideally at this time, the ends of the tie cables leading to and from the street cabinet should also have been isolated, secured from further damage and protected from the elements. The database restore process can be performed at this point (even prior to arrival of the trailer cabinet assembly).

3. .. Upon arrival at the site, the trailer cabinet assembly is initially connected' via cable ducting (26) to the modified footway box cover or lid.(28) as shown in e.g. Figure 10. The connection at each end of the ducting is preferably secured and a set pair within the tie cables connected to the cable alarm: It is not essential however that the cabinet assembly be used at the actual location of the original footway box at tfle actual disaster site itself, because the trailer cabinet assembly can be connected to a more convenient footway box within 50m instead. Operatives work bring the cables (54) of the underground network in the fdotway box (56) to the ground surface, and bring them through the ducting (26) into the interconnect compartment (10) of the trailer. The trailer is then movd into the position shown in Figure 11, wherein the interconnection compartment (10) is located substantially above the footway box covered by the modified lid (28). . 4. The operative opens the doors ofthe interconnects compartment as depicted in Figure 5, and reconnects customers by making the necessary connections between customers and the exchange on the interconnections block in the copper flexibility compartment. Usefully, reconnections in this compartment never vary owing to the unchanging tie cable links between the intercoFinection and DSLAM compartments.

The cabinet assembly can remain functional at thedisaster site for as long as the street cabinet remains inoperative. . The apparatus, methods and configurations described above and in the drawings are for ease of description only and not meant to restrict the invention to any particular embodiment. It will be apparent to the skilled person that various sequences and permutations on the apparatus and.memods described are possible within the scope of this invention as disclosed.