domotics chapter 5

8/10/2019 Domotics Chapter 5

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H

omeofthe

Future

eBook

Guy KasierE&D Systems

July 2008

Structured cablingin the home


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www.leonardo-energy.org Structured cabling in the home

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Structured cabling in the home

1. Introduction

It used to be a lot easier. It used to be that 230V cabling would be laid in the newlybuilt home, to which a few sockets, power points and switches were connected. Atmost, there was also a telephone socket in the wall and a coax cable connection forthe television. A small distribution board was sufficient to protect a few socket circuitsand lighting circuits. The installation was ready.

That is no longer the case today. With the arrival of integrated home systems andmany other technological marvels of this day and age, the number of networks in thehome has increased sharply. Generally, one telephone connection is no longerenough; we want to have a connection in almost every room. This is also the case forthe television and radio. In addition to the flat-screen TV in the living room, we alsowant a television in the bedroom and kitchen. And in the bedroom, we also want tobe able to watch and operate a DVD recorder with hard disk. Furthermore, we have adesktop computer and a few portable computers for which we also provide aseparate network. All these computers must also be able to use the Internet. There isa video entry phone at the front door that we want to use in various places in thehome. When we are watching television, the picture of the person at the doorappears as a PIP (picture in picture) on the screen, and why not on the computerscreen when we are using the computer as well. Furthermore, we would also like to

hear our entire MP3 collection on the audio system in the living room and the audioequipment in the childrens rooms. In the bathroom and kitchen, we want to listen tothe news on the radio. We also want to use IP cameras on certain televisions and thecomputers.

The expansion of the various networks in the home is enormous. It is then obviousthat we are looking for solutions for dealing with such network cabling in the home ina well thought out way. In this article, we will discuss a few practical examples andsmart solutions. We will see that the flexibility (the adaptability) of the installation willplay an important role.


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2. The basics

Depending on the systems that have to be cabled, we generally use two cablingmethods. The first is to connect from component to component. This method is used,

for example, when the operating points of an integrated home system are connectedto a bus system via a decentralised interface. In practice, we come across this formof cabling in the EIB/KNX integrated home system.

Figure 1:Connection of operating points to the same bus cable. (Illustration source: E&D Systems)

The advantage of this form of cabling is that only a few connections have to be

made. The disadvantage is that there will be a greater loss of function when thecable is damaged. A second cabling method, that we will use a lot more in practice, isstar cabling or home run. Every component is connected to a central point by itsown cable. There are many examples of this, such as the telephones that areconnected to the local telephone exchange with their own cabling, or the speakers ofa multi-room system that are connected to the central amplifiers with their owncabling as well. The most well known example is probably the computer networkwhere every computer has its own connection to the hub or router.


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Figure 2:A Gira EIB/KNX button is connected to the bus cable here. We see two red and two black cables. The

bus comes to the connector and then goes on to the next component. (Illustration source: E&DSystems)

Figure 3:Integrated home system buttons that are connected to a central point using a star topology.


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Figure 4:Example of an audio system and a telephone system in which every component is connected to a

central point by its own cabling. (Illustration source: Russound)

The advantage of star cabling is that there is only a limited loss of function when acable is defective. The disadvantage is that a lot of connections have to be made atthe central point.

3. The traditional installation method

For every room in the home, a decision has to be made regarding which connectionsand how many of them have to be put in, and where to locate them. How manyphone connections do we want in the living room? Will there be a fax machine there?Where should the connection for the television and radio be? Must there also be aconnection for the computer network in the living room? Where will the home theatrespeakers be? We can continue like this for every room.

The traditional installation method consists of linking every connection to a centralpoint with its own cable. On the one hand, this entails a lot of cabling work and


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Figure 6:The Bticino multimedia solution uses two cables. (Illustration source: Bticino)

4. Smart installation methods

If we just carry on directly connecting everything at the central point to the activeunits, then there continues to be a problem regarding the flexibility of the installation.It is better to use a patch cabinet, in which every individual cable comes to an outletin the cabinet. We can now make the correct connection using patch cables. We canalways decide whether we will use an outlet in the home for a computer connectionor for a telephone or fax machine. Certain manufacturers go much further here andonly use one cable for telephony, audio, video, television and computer connectionsthroughout the home. We will look at a few concrete examples.

4.1. Abitana

Abitana uses its own cable. It is a screened TP cable with four pairs of conductors.One pair of conductors in the cable is screened separately. This pair can be used forthe distribution of video and television signals.


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Figure 7:The Abitana cable, in which the brown-white pair is screened separately. (Illustration source: Abitana)

All RJ45 outlets throughout the home are connected in a star topology to a separate

multimedia distribution board by this cable.

Figure 8:The multimedia distribution board. (Illustration source: Abitana)


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All incoming cables are connected to an RJ45 outlet in this distribution board. Theseoutlets are mounted on the DIN rail. Depending on the residents desires, one ormore active components can also be incorporated into the multimedia distributionboard, e.g., video distributors, a hub or router, an audio distributor, a telephonedistributor, etc. An outlet in a certain room can be connected to any active component

by using patch cables. In practice, this means that, for example, an unused outlet inthe childrens room can be connected to the local telephone exchange, because younow want to use a fixed telephone there as well. If you decide to take the telephoneout of the room, but you still want a data connection for the computer or a TVconnection, then it can be done in no time at all in the patch cabinet.

Figure 9:Left: a TV distributor that is secured to the DIN rail in the patch cabinet. Right: the coupling from an

RJ45 outlet to a coax connection for the television. (Illustration source: Abitana)

In order to further increase flexibility, splitters are also supplied. These ensure that anRJ45 outlet can be used not just for one unit, but also for a number of units. Forexample, two telephones can be connected to one RJ45, or a telephone and acomputer, etc.


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Figure 10:Distribution of antenna or CaTV signals throughout the home. (Illustration source: Abitana)

4.2. Gardy

Gardy (Schneider Electric) also has a similar solution to Abitana, under the name ofFreedomnet. However, Gardy has the Freedom Multinet system specifically forhomes. This does not use a distribution board with separate components, but amultimedia distribution box. Up to 8 RJ45 outlets can be connected to it. Twotelephone lines, antenna or CaTV signals and a router can be used as the sources.In this way, each RJ45 outlet can be used for these different signals.

In order to be able to use an RJ45 outlet for a number of purposes at the same time,Gardy provides a multimedia splitter. This looks a little like a computer mouse. Thesplitter is connected to the RJ45 outlet in the room. On the other side, 3 units can be

connected: telephone, TV and computer.


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Figure 11:Distribution of telephone, computer and TV to 8 RJ45 outlets in the home. (Illustration source: Gardy)

Figure 12:Up to three units can be connected to one RJ45 outlet using the mouse splitter. (Illustration source:

Gardy)


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4.3. Reichle & De-Massari

Aside from the multimedia connection module that we discussed earlier, R&M alsohas a smart solution for the home in the form of a micro-splitter. To this end, a smallconnecting piece is plugged into an RJ45 outlet. R&M provides different patch cables

that have single or double micro-plugs. A single plug is sufficient for an analoguetelephone line. A double plug is used for TV signals and data communications. Alltypes of combinations are thus possible on one and the same RJ45 outlet: acomputer connection, an analogue telephone and a fax, or a computer connectionand a TV connection, etc. The function of each connection can be indicated withcoloured strips.

Figure 13:Top left: the small micro-splitter that can be plugged into every RJ45 outlet. Below: the various patch

cables for telephony, computer and TV. (Illustration source: Reichle & De-Massari)

5. Installation tips

Every producer provides sufficient information on how the outlets have to beconnected to the cables. For example, the length to which the outermost cableinsulation must be cut back is important, as is the length of the screening with STP orFTP cables. These instructions have to be strictly adhered to in order to ensureoptimum data communications.


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Figure 14:Example of the way in which a producer indicates how the connection has to be made to an outlet.

(Illustration source: Niko)

In addition, a number of general installation rules apply. Data cables must not bebent too tightly, otherwise the twisting of the conductor pairs in the cable will bespoiled. Generally, a minimum radius of 8 times the outside diameter of the cable isstipulated. Furthermore, there must be no mechanical tension on the data cables(also with regard to the twisting). Therefore, it is better to roll out the cables from areel that can turn freely.

Figure 15:Some important installation tips. (Illustration source: Niko)

You must also ensure that the outer sheath is not compressed when securing thedata cables in place. Finally, it is also important not to place data cables too close to230V cables, in order to avoid interference.


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6. Links to producers

Abitana: www.abitana.com

Bticino: www.bticino.comGardy: www.gardy.comGira: www.gira.comNiko: www.niko.beReichle & De-Massari: www.rdm.comRussound: www.russound.com

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