Structured Wiring Systems - new wiki article

[John Rumm]

As usual, for your delectation / derision etc:

free to comment here or make mods to the article itself.

[Charles Fearnley]

An excellent new page John, which I wish I'd seen before starting my own (currently incomplete) structured wiring.

One small possible addition/clarification to the telecoms section - LAUs are mentioned, as the standard method of adapting phones with BT plugs to the RJ45 sockets. However, the majority of currently available phones are in fact two wire phones, which with a suitable cable (RJ11 to RJ11 or RJ45) can be plugged straight in, and will work fine with simple (non PBX) phone systems. Older three wire phones will indeed need a LAU in order for ringing to occur correctly. This might be worth mentioning?

Charles F

[Graham.]

I have only had a quick look but it seems excellent work. Something needs to be said about solid vs. stranded UTP. A section about making patch-leads.

What would your opinion be about advising someone who is DIYing their own installation, and also making a number of patch leads to buy stranded UTP, and use it for both permanent wiring and patches, as stranded does krone OK?

[Andrew Gabriel]

Patch leads are so cheap (if bought from the right places) that I struggle to think anyone would normally make them. (Having said that, I do occasionally make them, but only for very strange reasons, not for bog-standard patches.)

[RubberBiker]

Thanks for an excellent article John - and for me,timely!

Regarding video distribution - what are the pluses/minuses of using HDMI rather than cat5e ?

Would it be worth saying something about terrestrial tv/satellite tv/ coax/distribution amps?

Is it practical to incorporate a coax patch panel in the same rack along with a distribution amp?

What about cabling in home cinema?

Are any domestic fire alarm/intruder alarm systems readily compatible with structured wiring?

It might be worth linking to useful wikipedia articles, e.g.:

to mention the relevance of cat6:

appreciate that's a considerable expansion from the original scope - but even one sentence on each topic to raise awareness makes a difference (and hopefully later returns a fully-crafted article from another reader!).

[Adrian C]

FWIW I trail a lot of network cables around here. Not much into making things permanent with wall / rack mounted sockets, so every cable is male-male threaded through holes peppered through walls.

For the loose supply of RJ45 connectors there seems to be different types for stranded and unstranded (solid) cable.

I mostly use the unstranded type with solid cable which up to now[1] is just a single wires sort, shove and crimp thing that takes me a couple of minutes each.

[1] However at Maplin, they have "Solid Core Cable RJ45 Connectors" - Order code N20CH which consist of extra fiddly little plastic bits that when fiddled further with (and not lost down the back of the sofa [2]) nicely align the conductors for the final shove into the gold jaws of the IDC contacts.

to do, but takes longer to do once ye have the T-568B colour order ingrained in ya mind...

[2] Or whatever gap exists to lose life's wotsits and guarantee return trips back to the shop for more ...

[Dave Liquorice]

Patch leads are cheap. Even at minimum wage you can buy one for the time it takes.

Stranded will krone but how reliable it will be in the long term when the wiring gets fiddled with is another matter. Or even if it will tolerate the movement whilst the other cables are bing punched down and the panel moved into place.

[Dave Liquorice]

Quick read.

I'm not convinced about taping the cable bundles at intervals. It will stop you pulling one back to reroute to another destination in the future.

Tape the end that will be pulled in, all over the ends making a bit of a "point" to help it feed, without snagging, enroute but remove any along the body of the bundle.

[Dave Liquorice]

How far will HDMI go? I suspect it's only a short distance spec measured in metres...

That is whole new ball game with many variations depending on what the requirements are.

It might be worth adding that putting in at least one quality coax cable to every room is a good idea due to the disruption that putting cables in makes.

Surely that would be dedicated to the "cinema room" and comes in with the (short?) distance capabilities of HDMI?

[RubberBiker]

15 metres

To answer my own question, the recommended approach for long runs is a converter to use a pair of cat5e's:

It might be worth adding that putting in at least one quality coax

I'm told a pair of coax's to wherever a dish might be installed is also a good idea.

After posting, I thought of integrated/multiroom entertainment systems as well.

[dennis]

Five meters is the normal standard.. you will have to pay £5-£7 for a lead good enough to do that. It will probably work over twice that but it might not if there is a lot of interference from motors, etc.

There is no gain in audio or video quality if you buy £100 hdmi leads but some might work over a longer distance if they have used better cable rather than just dressing up cheap cable as most do.

You can buy hdmi extenders that use cat5 between the extenders, they weren't cheap when I looked but claimed to do >100m.

[John Rumm]

I was in two minds on that... my main reason for not including it was that the price of a LAU is not too different from that of a replacement lead for the phone anyway (since most sold for domestic use will have RJ11 to BT connections[1]), and at least the LAU is fairly fool proof - it will work with anything without needing knowledge of the phone.

[1] Although to be fair I did buy one the other day that came with both leads.

[John Rumm]

Yup, cable selection is worth adding.

Making patch leads is only worth doing IME when you need something unusual - i.e. long length, or the need to route a cable without the plug on the end. Generally speaking I buy them ready made - in 10's its unlikely you would need to spend more than 40p a lead. Obviously if you are looking at PC World shop prices then making them looks more attractive!

I would say buy solid core for everything. Even if you do use it for making up fly leads it still works well enough, and unless you are constantly moving the wire about, it will last.

[John Rumm]

HDMI is more a connection standard than a distribution one. You may find its the only method that will fully support the HDCP system end to end and hence not result in some lump of DRM getting the hump and deciding to bollox the video quality.

Yes, but not here!

In fact a sat distribution article might be worth having...

No reason why you can't. You might want a bigger rack if you are going to add this and a multiswitch, and distribution amps etc.

A separate article again I think...

With smoke alarms, most I have seen simply use three & E mains cable or radio for the interlinking.

Fire/heat/smoke detectors that integrate with alarms systems, would run on structured cabling, however I am not sure there is much benefit since these things tend to be hardwired and small discrete telephone grade cables are usually the order fo the day.

;-)

[John Rumm]

4 to a dish, and at least 2 to anywhere you want a receiver if you are using a multiswitch and want twin tuner decoders in each room.

Structured wiring can help with some of that certainly. Depends on how "high end" you want each room; bog standard PAL style TV is easy, 1080p HD with 5.1 surround in each room takes more work!

[John Rumm]

IME if you don't tape them together it is very easy to end up in a rats nest of a tangle when trying to pull half a dozen bunches under a floor etc. Even when they are taped up you still need to be very careful coiling and uncoiling so as not to end up with a knitting problem!

Generally I would add another pair of cables later rather than try to move an existing one.

Much depends on when you are installing though. If you have large sections of floor up or plaster off etc, you may find laying individual pairs as you go simpler than pre cutting a loom.

[The Natural Philosopher]

100% agreement from here. solid for fixed wiring, flexi for patch cords.

[Dave Liquorice]

coax

putting

Yes four to the dish, hi-band vertical, hi-band horizontal, lo-band vertical and lo-band horizontal.

Good point. To maintain the watch one channel, record another capabilty you need two feeds from the mutiswitch or LNB.

This is why a seperate wiki on TV ditsribution is a good idea, there are many variations depending on what is to be distributed, to how many points and what abilities are required at those points.

[Andrew Gabriel]

I presume you can only pass the high resolution encrypted video over HDMI?

They generally warn you not to use solid core cable. The terminations are designed for stranded alarm cable, and are significantly less reliable when used with solid core.

[dennis]

Do you mean that you

1: need hdmi to pass hdcp enabled digital content

or

2: hdmi can only pass encrypted high res video.

1 is true, 2 is not.

You wouldn't want to do it anyway.. its a problem if someone comes along and moves a patch cable to the wrong place on a network, its dangerous if its an alarm system.