WO2008099184A1

WO2008099184A1 - An interconnection system

Info

Publication number: WO2008099184A1
Application number: PCT/GB2008/000517
Authority: WO
Inventors: Peter Graham Long; Michael Fake; Richard Teal
Original assignee: Raymarine Uk Limited
Priority date: 2007-02-14
Filing date: 2008-02-14
Publication date: 2008-08-21
Also published as: GB0702882D0; GB2447066A

Abstract

An interconnecting connection system for enabling communication between a plurality of system components is disclosed. The system has a plurality of connectors, each connector having two first connection sockets and at least some of the connectors having a second connection socket. A plurality of first link cables are provided, each link cable interconnecting two connectors to form an elongate linkage comprising alternate connectors and link cables, ends of the first link cables engaging respective ones of the two first connection sockets of the connectors. A plurality of second link cables each have a first end engaging a respective one of the second connection sockets of said at least some of the connectors and a second end adapted to engage a system component.

Description

AN INTERCONNECTION SYSTEM

Background of the Invention Field of the Invention

The present invention relates to an interconnection system for interconnecting cabling for e.g. power and/or communication. The present invention is particularly, but not exclusively, concerned with a connection system for use in marine environments. Summary of the Prior Art

There are many situations where it is necessary to provide connections between various cabling and/or communication links, to enable them to be distributed around a structure such as a boat. In general, it is necessary for such a connection system to be simple to use, and permit reliable interconnection. It is also desirable for such connection to be able for use in a manner which avoids misconnection.

Summary of the Invention

The present invention starts from an arrangement in which a "backbone" is defined by a series of alternating connectors and link pieces, which can define a path along the interconnection system for the cabling. Other link ■ pieces may then form branches off that backbone, at the connectors, to enable connection to the cabling of the backbone. The use of a backbone structure provides for more efficient data communications than some other systems .

Thus, the present invention proposes that the interconnecting connection system may have a plurality of connectors each having two first connection sockets and at least some of the connectors having at least one second connection socket; a plurality of first link pieces, each link piece interconnecting a pair of connectors to form an elongate linkage comprising alternating connectors and link pieces, ends of the link pieces engaging respective one of the first connection sockets of the connectors; and a plurality of second link pieces, each having an end engaging a respective one of the second connection sockets of said at least some of the connectors.

The present invention, in its various aspects, is concerned with the features of that connection system, to enable one or more of various advantages to be obtained. Each of the various aspects may be used alone, or in any combination .

The first aspect is concerned with the engagement of the link pieces and connectors. It is important that the interconnection system is assembled correctly, with the appropriate link pieces being used to form the backbone, and other link pieces being used to form the branches . Each link pieces engages a socket of the corresponding connector, and it is desirable that the user cannot connect a link piece to form a branch into a socket intended to form part of the backbone, and vice versa. The interconnection of the link pieces and sockets is by the engagement of corresponding pins and holes, and according to the first aspect of the invention, the pattern of pins and holes for the link pieces and connector sockets which are to form the backbone have a different pattern from the pins and holes of the link pieces and sockets to form the branches.

Thus, according to this aspect of the invention, it is preferable that the engagement of the first connection sockets and the respective ends of the first link pieces being via a plurality of pins and holes, the pins being received in the holes, the pins and holes being arranged according to a first pattern and the engagement of the second connector sockets and the respective ends of the second link pieces being via a plurality of further pins and further holes, the further pins being received in the further holes, the further pins and further holes being arranged according to a second pattern different from said first pattern.

In such an arrangement, the pins may be on the link pieces, and the hole in the sockets, or vice versa.

It would be possible for the pattern of pins and holes in the first and second connector socket and link piece ends to differ by the position of only one pin and hole pair. However, such an arrangement is undesirable, because a user may be able to force a pin or hole from the "wrong" link piece to engage with an inappropriate socket. It would only need a small amount of deformation of the pin/hole structure. Therefore, it is preferable that the pattern of pins and holes is .completely different for the engagement of the link pieces and sockets to form the backbone from that pattern of the link pieces and holes to form the branches. If the two patterns are overlaid, none of the pins of one pattern is aligned with the pins of the other when the two parts are fitted together correctly. However, while such a complete mis-alignment is preferred, it may be possible for arrangements to be provided in which only some of the pins of one pattern are mis-aligned with the pins on the other pattern.

The second aspect of the invention is also concerned with the engagement of the link pieces and the connectors. In this aspect, a locking mechanism is provided at the junction of the link pieces and connectors, which prevents the link pieces and connectors being accidentally disengaged. Preferably, the locking mechanism is a rotary one, controlled by the rotation of a collar. That collar is preferably on the connector.

In such a locking arrangement, it is preferable that the collars and adjacent parts of the link pieces or the connectors have raised arrows, the alignment or misalignment of which indicates the unlocking and locking positions of the mechanism. The arrows are raised ones, because this provides both a visual and touch indicator to the user as to the locking and unlocking.

The third aspect of the invention also relates to the interconnection, and the use of pins and holes to link the link pieces and the connectors. In this third aspect of the invention, the pins are all on the connectors, and the holes are all in the ends of the link pieces. Thus, if the connectors and link pieces forming the backbone terminate at connectors, at the extreme ends of the backbone, those connectors are both "male" arrangement with pins, and thus connection to the ends of the backbone can adopt the same arrangement irrespective of the which end of the backbone needs connection thereto. Thus, a uniform system may be provided for all components to connect to the backbone.

The fourth aspect of the invention concerns the ability for the user to distinguish between the various components of the system. In particular, a colour coding of the components is chosen so clearly to distinguish between the backbone component and the branch component. Thus, the first link pieces, and the first sockets of the connectors may be of a first colour, and the second sockets and at least the ends of the second link pieces may be of a second colour. In this way, the use knows clearly whether the link piece is to form part of the backbone, or part of a branch. Moreover, it permits

"colour to colour" connection to prevent the components being assembled incorrectly. A further colour or further colours may be used to indicate other link piece functions, e.g. power. In the present invention, as described previously, the link pieces forming the backbone (the first link pieces) connect to respective connectors at their ends. There is no "link piece to link piece" connection. This again prevents the user assembling the system in an inappropriate way. It permits the separation of the backbone and any component attached to that backbone via a branch to be limited (by choice of the length of the second link pieces) , without the overall size of the system being too great.

In the present invention, the pattern of pins and holes is chosen primarily for appropriate interconnection of the components of the system described above. However, additional pins and/or holes may be provided for making the connection system of the present invention compatible with other link pieces and/or connectors.

In all aspects of the present invention, the connectors may be in the shape of a "T" with the arms of that "T" forming the backbone, and thus having the first connection sockets at respective ends thereof. The leg of the "T" may then form the connection to the branch, so that the second connection socket is at that leg end. However, it is also possible for the connectors to be in the shape of the cross, with two parts of that cross ending in the first connection sockets and the other two ending the second connection sockets, so that there are multiple branches from a single connector, or in the shape of an ^λΕ" with the first connection socket at the ends of the upper and lower arms and the second connection socket at the end of the middle arm. Multiple branched connectors may also be formed by a connector structure having first connection sockets at respective ends and a row of two or more second sockets along one side. It is also possible for one or more of the connectors to have no braches, so that it only has two first connection sockets. Such connectors then permits the length of the backbone to be extended between branches. Moreover, it is not necessary for a second link piece to be connected to every second connection socket. One or more of the second connection sockets may be closed with a blanking plug. Similarly, there may be a terminator plug at one or both ends of the backbone, inserted into a first socket of the endmost connectors.

In the discussion of the invention above, it has been assumed that the various components are all interconnected, to form a system. However, the present invention also includes a kit of parts for enabling such a connection system to be assembled. Such a kits of parts may then have a plurality of connectors, each having two first connection sockets and at least some of those connectors having at least one second connection socket. The kit will then have a plurality of first link pieces, each link piece being arranged to interconnect a pair of connectors, with ends of the link pieces being engagable in respective ones of the first connection sockets of the connectors. The kit also has a plurality of second link pieces, each having an end engagable in respect one of the second connection sockets. Then, such a kit may incorporate one or more of the various aspects of the invention discussed above.

Moreover, the present invention further includes a method of assembling such a system according to any of the aspects above, comprising inserting the various link pieces into the corresponding sockets of appropriate connectors .

Brief Description of the Drawings

An embodiment of the present invention will now be described in detail, by way of example, with reference to the accompanying drawings, in which:

Fig. 1 is an exploded view of a connection system in accordance with the present invention; Fig. 2 is a sectional view through a connector (without locking collars) used in the system of Fig. 1;

Fig. 3 is a view of one end of the connector of Fig. 2; Fig. 4 is a view of another end of the connector of Fig.2; and

Fig. 5 is an external view of the connector of Fig. 2 (with locking collars) .

Detailed Description

Referring first to Fig. 1, a connection system comprises a plurality of connectors 10, interconnected by a plurality of cables 12 forming links between the connectors 10. Each cable 12 terminates at its ends in plugs 14 which are received in sockets 15 in the connectors 10. As will be explained in more detail later, the plugs 14 and sockets 15 have a pattern of pins and holes which enable the cables 12 and connectors 10 to be interconnected.

The resulting structure of connectors 10 and cables 12 form a backbone of the interconnection system, to which other linkages may be made as branches off that backbone. Thus, Fig. 1 shows three other cables 16 17 18, one end of each of which terminates in a respective plug 16a, 17a, 18a, which plugs 16a, 17a, 18a are received in corresponding sockets 21 of the connectors. Again, the plug 16a, 17a, 18a and the sockets 21 have a pattern of pins and holes to enable satisfactory interconnection. The cables 16, 17, 18 may have different purposes. Thus, for example, the cable 17 may be a power cable, and the cable 16, 18 may enable the backbone to be connected to other components via plugs 16b 18b.

Fig. 1 also shows terminator plugs 19 which are inserted into sockets 20 at the ends of the backbone. In fact, the sockets 20 are identical in configuration to the sockets 15, and thus the plugs 19 and sockets 20 will have the same pattern of pins and holes as the plugs 14 and the sockets 15.

As can be envisaged, the structure illustrated in Fig. 1 may be extended by additional sockets 10 and cables 12. It may thus be of any length. It is also possible to use connectors in which there are two sockets 15, but no socket 21, so that the connector merely forms part of the backbone structure linking cables 12, and it is not possible to form a branch at that connector. Similarly, it is possible to have connectors with multiple sockets 21, so that there may be multiple branches at the connector. Such multiply branched connectors may form a cross-arrangement, or even have the multiple sockets 21 in a linear arrangement.

Fig. 2 shows the connector 10 in more detail. The connector has a body 30 supporting two rings 32 at opposite ends, the opening 33 in those rings 32 then receives the sockets 14. There are pins 34 projecting into the interior of the rings 32, to enable connection to the plugs 14.

Fig. 3 then shows an end view of the sockets 15 formed by ring 32 and pins 34. As can be seen, the periphery of the opening 33 is not round, but has flat faces 35 which enables the fitting of a locking collar

(to be discussed later) . There is also an alignment projection 36 which fixes the orientation of the plug 14 into the socket 15.

Similarly, the socket 21 has a ring 40 into which the plugs 16a, 17a, 18a, as appropriate is received, again having an opening 41 for receiving those plugs and pins 42. The pattern of those pins 42 is then shown in more detail in Fig. 4. Again, the opening 41 has flat sides 43 again to enable the fitting of a locking collar and an alignment projection 44 which determines the alignment of the plug 16a, 17a, 18a in the socket 18.

It can be seen from comparison of Figs. 3 and 4 that the pattern of pins 34, 42 is different in the sockets 15 and the socket 21. In the pattern of pins 42 of the socket 21, there is a central pin, with the other pins arranged around it. The pins 42 are arranged so that none are aligned with the axis of the sockets 15. On the other hand, the pins 34 are arranged in the pattern with no central pin and two of the pins are aligned with the axis of the socket 21.

The plugs 14 have a pattern of holes (illustrated at 14a) into which the pins 34 are received. Similarly, the plug lβa, 17a, 18a have a pattern of holes (illustrated at Iβd, 17d, 18d) into which the pins 42 are received. Because the pattern of the pins 34 is different from the pattern of the pins 42, the pattern of holes 14a is different from the pattern of holes 16d, 17, 18d. As a result, the plug 14 cannot successfully be inserted into the socket 21, and the plug 16a, 17a, 18a, cannot successfully be inserted into the sockets 15.

Note that the terminator plugs 19 have the same pattern of holes (illustrated at 19a) as the pattern of holes 14a, so that they are received in the sockets 20.

The sockets 20 have the same pattern of pins as the sockets 15.

In such an arrangement, the spacing between the connectors 10 is determined by the length of the cables 12. It is thus possible to restrict the spacing between the points along the backbone at which the branches can be connected. Moreover, it is possible to link the separation of the connectors 10 and any components thereto connected by e.g. the cables 16, 18. This enables a restriction between the distance between the backbone and any components attached thereto to be achieved, which may be desirable to enable the system to provide efficient communication between those components.

Although not shown in Fig. 2, the body 30 of the connector 10 provided interconnections between the pins 34, 42 to enable power and/or data paths to be formed through the connection system via the braches and along the backbone. The pattern of such connections will depend on the particular functions of the branches formed by- cable 16, 17 and 18.

Moreover, in the arrangement illustrated in Fig. 1, the cables 12, 16, 17, 18 are all straight. It is also possible to provide angled cables if needed to ensure that the backbone and the branches may follow appropriate paths .

It is also preferable that the components are colour-coded to prevent mis-connection. Thus, for example, the cables 12, their plugs 14 and the sockets 15 to which they are connected may all be coloured a first colour (e.g. blue) . At least the plugs 16a, 17a, 18a and the sockets 18 to which they are connected may similarly be colour-coded, in a different colour (e.g. white). A further alternative is to colour-code the power cable 17 a third colour (even though its plug 17a may be the second colour) . Thus, the user has an immediate visual indication of which plugs are to be connected to which sockets, and vice versa. The possibility of mis- interconnection is thus further enhanced. The colour- coding of the cables 12 and sockets 15 also provides an immediate visual indication of the path of the backbone through whatever structure (such as a marine vessel) the connection system is mounted.

In the embodiments illustrated in Fig. 1, the plugs 14, 16a, 17a, 18a, lβb, 18b are all moulded into their respective cables 12, 16, 17, 18 to avoid mis-connection if the user were accidentally to try to cut and splice the cables. All the components should be waterproof, at least for marine environments . Preferably, the profile of the plugs 14, lβa, 17a, 18a, 16b, 18b are all relatively small, e.g. less than 11.5mm diameter, for convenience.

As has been discussed above, the different patterns of pins and holes on the plugs 14 and sockets 15, and on the plugs 16a, 17a, 18a and the sockets 21 prevent a cable 12 intended to form part of the backbone being connected to the sockets 21, or a cable 16, 17, 18 to form part of a branch to be connected to the sockets 15. The colour-coding of the cables also reduces the risk of mis-connection. However, it remains possible in the arrangements described above for a cable accidentally to become detached from a socket, if e.g. it is pulled. Therefore, it is preferable that there is a locking mechanism for locking the plug to the socket. This is illustrated in Fig. 5.

Fig. 5 shows the exterior of the connector 10 shown in e.g. Fig. 2. Each socket 15, 21 has a collar 50, which provides locking. The collars 50 are mounted on the rings 32, 40 shown in Fig. 2. As shown in Fig. 2, the rings 32, 40 may have grooves formed in an outer surface thereof, to enable the collars 50 to be held in place. The collars 50 then provide locking of the plugs 14, 16a, 17a, 18a in the sockets 15, 21.

Fig. 5 shows that each collar 50 has a raised arrow 51 thereon, and there is also a raised arrow 52 on the adjacent parts of the body 30 of the connector 10. When the arrows 51, 52, are aligned, as shown in Fig. 5, then the collars 50 are in their un-locking position. When the collars 50 are in that position, the cables 12, 16, 17, 18 as appropriate, can be inserted or released.

Rotation of the collar 50 from that position locks the cables in place. The arrows 51, 52 are raised, so that they can be detected both by touch and sight. The former may be important if, e.g. the connector is in a relatively inaccessible place. With such an arrangement, the collars 50 are then colour-coded in a similar way to the cables, sockets, etc. so that the collars 50 of the sockets 15 have the same colour coding as the cables 12, and the collar 50 on the socket 21 has the same colour coding as at least the plugs 16a, 17a, 18a of the cables 16, 17, 18.

The locking mechanism itself may be relatively conventional, with the rotation of the collars 50 causing alignment or mis-alignment of grooves or projections in the collars being aligned or mis-aligned with corresponding projections or grooves on the plugs 14,

16a, 17a, 18a. Moreover, for marine environment it may also be useful for the collars 50 to provide a measure of water ingress resistance.

Thus, the present invention enables a connection system to be provided in which the various components can be interconnected quickly, easily, and without mistake. Although the connectors have been designed specifically to be adapted for the connection of appropriate cables, they may further be adapted to allow other cable or components to be fitted to the structure, to enable the arrangements of the present invention to be retro-fitted in existing systems, or have components of existing systems connected to the connection system of the present invention. Since the components, and their connections, are standardised, the number of components needed to assemble an appropriate system can be minimised.

Claims

CLAIMS :

1. An interconnecting connection system for enabling communication between a plurality of system components, the system having: a plurality of connectors, each connector having two first connection sockets and at least some of the connectors having a second connection socket; a plurality of first link cables, each first link cable interconnecting two connectors to form an elongate linkage comprising alternate connectors and first link cables, ends of the first link cables engaging respective ones of the two first connection sockets of the connectors; and a plurality of second link cables, each having a first end engaging a respective one of the second connection sockets of said at least some of the connectors and a second end adapted to engage a system component.

2. An interconnecting connection system according to claim 1, wherein: the engagement of each end of each first link cable and the respective first connection socket is via a plurality of pins and holes, the pins being received in the holes, the pins and holes being arranged according to a first pattern; and the engagement of each first end of each second link cable and the respective second connector socket is via a plurality of further pins and further holes, the further pins being received in the further holes, the further pins and further holes being arranged according to a second pattern different from said first pattern.

3. An interconnecting connection system according to claim 2, wherein when the first pattern and second pattern are overlaid none of the pins of one pattern is aligned with the pins of the other.

4. An interconnecting connection system according to claim 1, wherein the first connection sockets of the connectors are each provided with a plurality of pins and the respective ends of the first link cables are each provided' with a corresponding plurality of holes, engagement of the pins of the connection sockets in the holes of the respective ends of the link cables providing engagement between the link cables and the connectors.

5. An interconnecting connection system according to claim 4, the system further having two terminator plugs provided with a plurality of holes, the terminator plugs engaging first connection sockets of the ones of the connectors at either end of the elongate linkage, the engagement being via engagement of the pins of the connection sockets in the holes of the terminator plugs.

6. An interconnecting connection system according to any one of claims 1 to 5, wherein the engagement between the link cables and connectors is lockable by locking mechanisms provided at the junctions of the link cables and connectors .

7. An interconnecting connection system according to claim 6, wherein each locking mechanism includes a collar provided on the connector at the respective connection socket, rotation of the collar relative to the connector causing the locking mechanism to become either locked or unlocked.

8. An interconnecting connection system according to claim 7, wherein the collar of each connector and adjacent part of the respective link cable each have raised arrows, the alignment or mis-alignment of which indicates whether the locking mechanism is locked or unlocked.

9. An interconnecting connection system according to any one of claims 1 to 8, wherein the first link cables and the first sockets of the connectors are a first colour, and the second sockets and at least the first ends of the second link cables are a second colour, sockets and cable ends of the same colour thereby being engageable .

10. An interconnecting connection system according to claim 9 as dependent on claim 5, wherein the terminator plugs are the first colour.

11. An interconnecting connection system according to claim 9 as dependent on claim 7, wherein the collars provided at the first connection sockets of the connectors are the first colour and the collars provided at the second connection socket of the at least some of the connectors are the second colour.

12. A method of assembling an interconnecting connection system according to any one of claims 1 to 11, including the steps of: interconnecting the first link cables and connectors by engaging the ends of the first link cables with respective ones of the two first connection sockets of the connectors; and engaging an end of each of the second link cables in a respective one of the second connection sockets of said at least some of the connectors.

13. A kit of parts for an interconnecting connection system for enabling communication between a plurality of system components, the kit having: a plurality of connectors, each connector having two first connection sockets and at least some of those connectors having a second connection socket; a plurality of first link cables, each link cable being arranged to interconnect two connectors to form an elongate linkage comprising alternate connectors and link cables, each end of each link cable being engagable in a respective one of the two first connection sockets of a connector; a plurality of second link cables, each having a first end engagable in a respective one of the second connection sockets of said at least some of the connectors and a second end adapted to engage a system component.

14. An interconnecting connection system for enabling communication between a plurality of system components, the system having: a connector having a connection socket and a collar; and a link cable having an end engaged with the connection socket of the connector, wherein rotation of the collar relative to the connector causes the engagement between the link cable and the connection socket to become either locked or unlocked.

15. An interconnecting connection system according to claim 14, wherein the connector has a plurality of connection sockets and a plurality of collars, one collar being provided for each connection socket, and the system includes a plurality of link cables, each having an end engaged with a connection socket of the connector.

16. A method of assembling an interconnecting connection system according to claim 14 or claim 15, including the steps of: engaging the end of the link cable in the connection socket of the connector; and rotating the collar relative to the connector so that the engagement between the link cable and the connection socket becomes either locked or unlocked.

17. A kit of parts for an interconnecting connection system for enabling communication between a plurality of system components, the kit having: a connector having a connection socket and a collar; and a link cable having an end engagable with the connection socket of the connector, wherein the collar is arranged to be rotatable relative to the connector, rotation of the collar when the link cable and the connection socket are engaged causing the engagement to become either locked or unlocked.

18. An interconnecting connection system for enabling communication between a plurality of system components, the system having: two connectors, each connector having at least two connection sockets with a plurality of pins; and a link cable having two ends, each end having a plurality of holes, wherein each end of the link cable is engaged with a respective one of the connection sockets of a respective one of the connectors via engagement of the pins of the connection socket in the holes of the end of the link cable .

19. An interconnecting connection system according to claim 18, having a plurality of link cables with ends having a plurality of holes and a plurality of connectors with at least two connection sockets having a plurality of pins, each link cable interconnecting two connectors to form an elongate linkage comprising alternate connectors and link cables, ends of each of the link cables engaging respective ones of the connection sockets of the connectors, the engagement of the connection sockets and link cables being via engagement of the pins of the connection sockets in the holes of the ends of the link cables .

20. An interconnecting connection system according to claim 18 or claim 19, wherein the system further has two terminator plugs provided with a plurality of holes, the terminator plugs engaging respective ones of the connection sockets of the connectors which are not engaged by an end of a link cable, the engagement being via engagement of the pins of the connection sockets in the holes of the terminator plugs .

21. A method of assembling an interconnecting connection system according to any one of claims 18 to 20, including the step of engaging each end of the or each link cable with a respective one of the connection sockets of a respective one of the connectors via engagement of the pins of the connection socket in the holes of the end of the link cable.

22. A kit of parts for an interconnecting connection system for enabling communication between a plurality of system components, the kit having: two connectors, each connector having at least two connection sockets with a plurality of pins; and a link cable having two ends, each end having a plurality of holes, wherein each end of the link cable is engagable with a respective one of the connection sockets of a respective one of the connectors via engagement of the pins of the connection socket in the holes of the end of the link cable .

23. An interconnecting connection system for enabling communication between a plurality of system components, the system having: a connector having two first connection sockets and a second connection socket; two first link cables, each having an end engaging a respective one of the first connection sockets of the connector; and a second link cable with an end engaging the second connection socket, wherein the first connection socket and the first link cables are a first colour and the second connection socket and at least the end of the second link cable are a second colour.

24. An interconnecting connection system according to claim 23, wherein the system has: a plurality of connectors having two first connection sockets; and a plurality of first link cables, each first link cable interconnecting two connectors to form an elongate linkage comprising alternate connectors and link cables, wherein the first connection sockets of the plurality of connectors and the plurality of first link cables are the first colour.

25. An interconnecting connection system according to claim 24, wherein each of the connector or connectors has a collar provided at each connection socket, rotation of the collars relative to the connector causing the engagement between the link cables and the connectors to become either locked or unlocked, wherein the collars provided at the first connection sockets are the first colour and the collars provided at the second connection sockets are the second colour.

26. A method of assembling an interconnecting connection system according to claim 24 or claim 25, including the steps of: engaging the ends of the first link cables with a respective one of the first connection sockets of the connector; and engaging the end of the second link cable with the second connection socket of the connector, such that each junction of link cable and connector is either the first or second colour.

27. A kit of parts for an interconnecting connection system for enabling communication between a plurality of system components, the kit having: a connector having two first connection sockets and a second connection socket; two first link cables, each having an end engagable with a respective one of the first connection sockets of the connector; and a second link cable with an end engagable with the second connection socket, wherein the first connection socket and the first link cables are a first colour and the second connection socket and at least the end of the second link cable are a second colour.