STP cable and IDC terminals

I'm considering using STP cable from my master socket to my ADSL outlet elsewhere, and hard wiring the cable.

What's the story with terminating STP cable at both ends into IDC terminals and the grounding/bonding implications?

I've searched the web, but there seems to be little info on this. Anyone done this?

For IDC, it will depend on the size of conductor. Good IDCs should be able to take 22 AWG (.65mm) up to 28 AWG (.32mm) - although it is preferable to stay with 24/26 AWG. (.51/.41 mm)


I recently changed the lead from ADSL socket to modem/router from a standard flat telephony cable to 2 pair cat5e with RJ11s fitted. Same an improvement of around 1.5 to 2 dB on the SNR.

Do you need the screening or will UTP be adequate?

I'd prefer STP since the cable will be running along eletrical cable runs, and terminating next to sockets with lots of kit at either end, so just trying to minimise any interference.

I'm just not sure about the shielding aspect of things at the IDC terminals.

If you could see where mine is - it is close to and goes past, ISDN NTE. ISDN switch and digital to analog telephony converters, PSUs, Burglar Alarm with all circuits and very basic PSU, 2 WAPS and PSUs, 24 port switch, CFLs, LED lights (with integral 240 to low voltage converters).


If you use STP, then you will may need to find a suitable earth connection, although the shielding alone may be adequate without earthing. It could be a case to play around to see what is best.

As there is no provision for the screen connection on most IDC faceplates, I'd take an earth from the nearest electrical outlet if it is for a couple of cables.
In the very few cases I've had to install STP cable, I've connected the screen to an earth at the central (patch panel) end with a dedicated earth to the nearest consumer unit or ideally the main earth point of the property.
Got plenty of standard UTP installations in some very electrically hostile environments and have had no issues.

Well the current setup is as follows:

Master socket has NTE5 splitter faceplate with telephone and ADSL outlets. I have a Cat5 low-grade cable running about 18Mtr from the router to the PC through two rooms.

The new setup will have one of these, and using the IDC terminals, I'll hardwire my chosen cable to the other room. It should require 20Mtrs in total (including over estimation and slack).

Additionally, I'll hardwire the phone terminals too for moving the master phone base to the PC room. I have a 20+Mtr phone cable (three pair) for this, but might use three of the six unused Cat'x' cable wires if that seems more useful.

Then at the PC area I'll have a wall port with a couple of modules for ADSL and phone. This isn't to be a LAN as such, but I want to get the most out of my ADSL cable (as little interference as possible). I'm guessing that STP is overkill for this, but just want to toy with the idea, and throw around the options for ADSL and phone cabling for future proofing.

My master faceplate and my router both have RJ-11 females for connecting the ADSL, so need to keep that in mind (my cable is RJ-11 male at each end).

Lots of little annoyances basically.

Edit: Something threw the swearfilter into gear. Edited.

Edited by camieabz (Mon 23-Aug-10 18:33:38)

Have a similar setup mine is an adsl nation version, just use normal cat 5, use 1 pair for adsl and another for phone, no ring wire as the phone works without it and have a 2 outlet cat5 face plate one port for the ADSL and the other for the phone with an adaptor to convert from rj45 to BT.

If you consider how far the adsl has travelled, the very small length of stp is not going to do alot.

Going_Digital should be able to answer this for you... The wikipedia article on Cat6 suggested that cable should be grounded on both ends for maximum efficiency, however I believe Darren (going dig) once said it should only be shielded at one end.

That is, if I am understanding what you are asking

Well that's part of it, but really just what you ground it to?

I could easily rig up a connection from a 240V socket, but I wouldn't normally even consider such things, as in my mind that's not a great idea. I don't tend to mess around with mains power from anything other than mains power.

Based on what I've read, grounding at both ends can result in earthing loops, while one end seems better, however many recommend both ends...

...and are we talking of the outer sheath only or the individual sheaths for each pair?

Never used the stuff so have many unanswered questions.

I have a sneaky suspicion that I'll be using solid Cat6 UTP. The stuff with the plastic seperator within. Seems best, and removes the need for all this added thought for probably little gain.

Anyone have any reliable sources for such cable btw?

Ideally the cable should be earthed with a dedicated clean earth at either end.

In practice you are unlikely to have a clean earth, and a noisy earth will be worse than no earth. Earthing the shield at both ends to the same earth will create a conductive loop, which can cause problems, and earthing at one end turns the shield into an aerial for all the local RFI.

You'd probably be better off with good quality UTP cable.