Home Communications Cabling
Overview
568A? 568B? What the?
Cabling systems
Sharing a VCR
or Set Top Unit to multiple TVs.
ADSL Central
Filter
Overview
This basic guide is produced in answer to the many emails I get
concerned with cabling homes for Data and communications, which
is related to my main line of business through OzTechnologies.com
(although I don't get the chance to get out on the tools much
myself these days).
There are a variety of options when it comes to cabling a house,
and several guidelines and industry standards that need to be
followed. Communications Cabling must be carried out by a licensed
Cabler. Penalties can be applied under the Telecommunications
Act for non-compliant cabling or equipment so think twice before
you DIY or trust a newbie to do it for you. Aside from the safety
issues, the last thing you want is to pay to have the whole job
done again because it wasn't done correctly the first time.
I've seen so many bad jobs (eg incorrect/inappropriate materials,
wrong layout, faulty equipment, incorrect terminations and so
on) that it's just not funny any more.
Some things to ask your Cabler -
Does he/she have an ACMA
license and what level is he/she licensed for?
Does he/she have 3rd party property damage cover?
What testing procedure/equipment will be used?
What guarantee is offered?
What experience does he/she have?
Wiring Patch leads
When wiring patch leads a common misconception is that "she'll
be right as long as the colour code matches on both ends".
Whilst this may work over short distances, for the most part nothing
could be further from the truth. I get a lot of work cutting ends
off Cables wired in the incorrect sequence causing slow Network
access, data loss or just plain not working at all.
The unfortunate thing about matching the ends is that the relatively
cheap Pair Testing Meters will usually indicate a thumbs up even
though it's just plain wrong.
The same goes for Keystones (sometimes called mechs). The colour
indicated on the Keystone must be adhered to or you will create
a lot of pain for yourself. The problem with most keystones is
that they are tiny and the little chart drawn onto them is hard
to read as they show two different wiring standards side by side.
568A & 568B.
| 568A Patch lead
With the clip part of the cable end facing away from you,
wires should go in the following order from left to right:-
White/Green - Green, White/Orange - Blue, White/Blue - Orange,
White/Brown - Brown
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| 568B Patch lead
With the clip part of the cable end facing away from you,
wires should go in the following order from left to right:-
White/Orange - Orange, White/Green - Blue, White/Blue -
Green, White/Brown - Brown.
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Ensure that the ends of the wires go all the way into the Clip
so that you can see the ends of the wires against the end of the
plastic, and if you don't have the proper crimping tool, don't
even bother starting.
Note: A crossover Cable uses 568A on one end, and
568B on the other.
Cabling systems
The first diagram below sets out the cheapest and most common
way to cable a home or small office.
The telephones are wired in a "peer to peer"
type sequence, so that if one rings, they all ring at the same
time, and several people can talk on the same call at the same
time. There are handsets available that allow a call to be transferred
from one handset to another, and can also double as an intercom.
 If an alarm
system that utilises a "mode 3" socket is to be installed,
then the mode 3 socket needs to be the first one in the series
after it enters the premises, and that's where the main control
panel for the Alarm will go too.
The data points are in a "star configuration"
(all branch out from a central point). This allows a desktop hub
to be fitted to allow all the PCs to be Networked together and
the Internet shared from either a server PC or a small router.
The Cable TV points are "star wired" from the
box outside at the Telephone Lead-in point as per Telstra/Optus
specifications.
If you're pre-wiring a new home, these rules must be followed
for Cable TV wiring.
A minimum of RG6 tri-shield Coaxial Cable with a solid dielectric
core must be used.*
The Cable TV Wiring must be run as per the diagram
to a point on the outside wall higher than 1 metre, but lower
than 2.4. (About chest height is ideal).
The side of the house you choose to run the cables to will
obviously be the one closest to the Telstra pit, or the tap
up the pole. Find where the phone and cable TV cables are in
your street and visualise how they'll get from there to your
house.
The splitter for all of the outlets must go in the
box outside the house (unless you're in a unit)
Terminations must be of the "F" Connector
type and torqued to specifications.
Any more than 3 active points will require installation of
an Amplifier at around $300.00
Anything outside of these rules, and the Cable TV installer will
be forced to rewire the whole lot, and your money and effort pre-wiring
will have been wasted.
Bear in mind that the Cable Networks are "sealed" networks
and the Communications Carrier (Telstra, Optus etc) in fact own
everything up to every socket and device (STU, Modem etc) and
are not obligated to connect you to their network if your wiring
is considered outside their specifications. The advantage in Pre-wiring
for Cable TV on a new home, is that you don't have to compromise
where the points will be and the Cabling will be properly hidden
from view.
*Update: Previously I had dual-shield co-ax
as a minimum (which was what it was when I was in the game) but
I have received a report form a very reliable source that Telstra
now require a minimum of Tri-Shielded co-ax cable while Optus
& Telstra Satellite require Quad-Shield. It may be well worthwhile
to check with your Cable provider before you fork out for the
wrong cable.
The diagram below shows the next step from a standard Cable job
on a home or small office.
In this situation we are installing a small PABX (Commander type
Phone System), and a patch panel for all the Data and Phone
sockets.
The main advantage here is that we can swap and change patch
leads to our heart's content down the track without having to
rewire anything, and all of the Networking Hardware and the Cable
modem is hidden from view in a cupboard.
You'll notice that now the telephones are now wired in
a "star configuration", and the PABX System and patch
panel will be mounted inside a cupboard, out of sight. We will
also be using Cat5E (Data Cable) for the Phones instead of the
standard "2 pair" Phone line. This will increase the
flexibility of the whole Cable installation and allow greater
scope for changes via the Patch Panel.
The data points are still in a "star configuration",
however now we have the central point in the cupboard where we
will also install the Cable modem and a small Router
to share the Internet Connection and Network the PCs together.
The advantage of a Router over a hub is that it doesn't rely on
a PC to be "always on" to share the Internet to all
the other PCs.
The Cable TV points are "star wired" from the
box outside at the Telephone Lead-in point as per Telstra/Optus
specifications mentioned above.
Ensure the
cupboard has louvered doors or some other method to allow air
circulation. Excessive heat and Networking Hardware don't mix
well...
A PABX system has many advantages over the standard method of
wiring for Phones. Features like having an internal intercom,
having several lines available at each handset and even being
able to answer the doorbell or unlock gates are available with
most PABX systems.
Expect to pay somewhere from about $1500.00 for a basic new system,
depending on the number of handsets and features required.
I installed a basic Aristel System
with two lines and four handsets, music on hold etc, Netgear JFS516
16 port Switch and patch panel on a mini rack/swing plate
in my home office for around $2000.00. This doesn't take into
account cabling or labour, but will give an idea of a starting
point for this type of installation.
Chuck and Emma have a
great Website which details the structured cabling installation
at their new home. Note the double
jumpering on the phone line (blue & white wires) on the
bottom row of the patch panel. This is the method necessary when
no PABX is to be installed (at least in the short term) so that
the (single) phone line can go to multiple points. These can now
be patched to various rooms using patch leads on the other side
of the patch panel (and changed around easily if circumstances
change). On my patch panel,
you'll notice little white cables coming in from underneath. These
come directly from my PABX and I can plug them into any socket
to go to any room or workstation where I have a data point installed.
Naturally I installed dual outlets everywhere so I can have both
a phone and data point active at the same time anywhere I choose.
Note: For those intending to DIY, note that there are legal
requirements for this type of work and they
did receive an unexpected visit from the Australian
Communications Authority to inspect the work and ensure it
was carried out correctly by a licensed cabler.
See my online
shop at OzTechnologies.com
for a selection of suitable Routers & Switches.
Sharing a VCR or Set Top Unit to multiple TVs.
These diagrams show a simple way to change the standard Free
to Air wiring in a house to share a VCR or Cable TV Set Top Unit
to multiple TVs in the home. The drawback with this system is
that although the TVs still maintain independent Free to Air control,
they all have to watch the same Cable TV channel at the same time.
There are infrared relays available that allow the Cable TV or
VCR remote to be used at other TV points by relaying the signal
back to the Set Top Unit or VCR
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ADSL Central Filter
In most situations, the ADSL signal runs down the
same line as an existing analogue service, but there are circumstances
where this is either inconvenient or involves an unnecessary expense
of leasing another line just for the ADSL signal. In other cases,
there may be another service which will not coexist with ADSL
or will adversely affect the ADSL signal.
Normally a small "in-line filter" is installed for each
handset or device that is on the same line as the ADSL service.
These filters prevent the screeching and crackling noise from
the ADSL modem from being heard whilst using the line for voice
and other purposes.
Other situations require that the filter is placed in a central
location before it gets to the other devices. These situations
are -
when the ADSL line is also on a PABX service
where a mode 3 Alarm Socket* is present on the ADSL line
where any hardwired devices exist on the ADSL line
where there are more than four sockets in use on a premises
on the ADSL line (This one may be more economics than anything
else, but having too many filters in the system may adversely
affect modem performance.)
A central filter will also get around difficulties with some
phones like many Panasonic Cordless units that don't seem to behave
very well with inline filters.
* A mode 3 alarm socket is a type of switching socket used for
back to base alarms. If the alarm is tripped while the phone line
is busy it will cut the call off to dial the alarm company. They
can tend to cause bad behaviour on ADSL whether or not an alarm
system is connected for some reason.
Note: For a mode 3 socket to be effective it must be the first
socket inline from where the phone line enters the building.
The diagram below shows the basic wiring format of a central
filter. The pictured filter is Telequip model No DSL019
2+ which is certified for ADSL 2+ lines as well as other ADSL
types.
Note the RJ11 socket on the DSL019 2+ labelled
"Alarm" is the one that goes to the first phone socket
or to the PABX system as the case may be. (The "Alarm"
socket has a built-in Mode-3 connection which will be handy if
it is going to an alarm system).
The socket labelled "Modem" goes directly
to the ADSL modem which will generally mean running a new line
to a new socket where the modem is going to be located.
Also bear in mind the cover comes off the DSL019
2+ to reveal terminals where the phone lines can be terminated
directly rather than using the RJ11 ports on the front. In 99%
of the central filter installations I've done I've had to cut
into the phone line before the first socket so using the internal
terminals would my preferred method of connection. Quicker and
easier than putting RJ11 ends on the cables anyway.
The image below is D-Link's 10SP Central Filter. Like the Telequip
DSL019 2+ above, the 10SP also has an RJ11 socket so the ADSL
modem can plug straight into it that way if you prefer, which
is very handy for those situations where the incoming phone line
is right next to where the modem is going to live. However, in
most cases a new line will need to be run for a new socket for
the ADSL modem to use and in these cases using the hard wired
terminal is more convenient.
Note: The instructions that come with the 10SP are a little
confusing as they outline a different method for connecting these,
which doesn't seem right to me and isn't the way I'd do it. 
Free Plug: I can supply & deliver central filters from
my online shop at www.oztechnologies.com.
We have installed heaps of the D-Link
10SP type units and have found them to be great, but we also
have the more recently released Telequip
DSL019 2+.
Which colour wires go where?
Ok, firstly you need to bear in mind that installing a central
filter or any other kind of work on a phone line is illegal
without the proper ACMA
license. I say this because if you don't know which wire is which
to start with you shouldn't be even considering doing this job
yourself. To find a licensed cabler try the OzCableguy Yellow
Pages from the left hand menu here or look for Cablers, Electricians
& Alarm installers in the Yellow Pages or your local paper.
Using a proper tradie also protects you from making an expensive
mess that might happen if you completely botch it up or drill
through a water pipe or electric wire etc.
Tip: Besides taking adequate safety precautions such
as wearing rubber soled boots and gloves, always find out where
the water and electrical mains are before you do any blind drilling
so you can turn them off quickly if need be.
Never grab a jammed drill bit or the chuck with your bare hands!
It might be hot but it might also have welded itself to a live
wire inside the wall. The drill casing is insulated. The chuck
is not and you may die if you touch it in this situation.
Save yourself the headache and hire a cabler.
For the cablers, most houses will have a single "2 pair"
phone line coming in. (One pair makes a circuit so there's provision
for a 2nd line in a 2 pair cable). 90% of the time the "A"
pair, ie blue and white, will be your first phone number. The
"B" pair, ie black and red wires, is for a 2nd line
or for emergency use in the case of a fault with the "A"
pair.
It's no big deal if you reverse the polarity. It will still
work fine, but mix up the "A" & "B" pairs
or cause a short and you're in for a world of pain. A short in
particular can cause the dial tone to black out back at the exchange
for up to 20 minutes or so which can cause a lot of wasted time
running around checking things even after you've fixed the problem
thinking there must be another one somewhere...
Some bright sparks at this point might realise they've got a
whole 2nd pair there they could use for the "modem"
side of the central filter to save running a whole new line. That
works (bearing in mind it'll be disconnected at each socket so
you'll have to pull all of those off and scotch lock the wires),
however it's a no-no. Do this and you run the risk of the
next cabler or fault technician on the premises swearing &
muttering stuff about 10 foot poles and getting back into his
or her van and driving away. There are standards. Stick to them.
There are penalities for not following the rules.
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