topic Re: Master Socket 5C MK4 wiring in Broadband & Landline

Master Socket 5C MK4 wiring

Rooster295 — Sun, 04 May 2025 15:29:07 GMT

Hello,

I have recently ently moved into a small property and have passed the EE activation date for my property. I am FTTC.

However, I have been having issues with set up and two engineer visits to the cabinet and to make sure I set things up right have not solved anything. Personally, I believe there is a problem with the Master Socket Wiring.

Everywhere I see talking about Master cable wires talks about blue, white orange etc. I have Red, Blue, Green and Brown. I have looked at the back and it is currently set up for Blue in A and Red in B, is this correct?

Re: Master Socket 5C MK4 wiring

XRaySpeX — Sun, 04 May 2025 16:19:39 GMT

Not according to

The nearest possibility is Pair #6.

What issues are you facing with your BB?

Re: Master Socket 5C MK4 wiring

JimM11 — Sun, 04 May 2025 16:22:25 GMT

@Rooster295 Why would you suspect a wiring issue, with 2 engineer visit's first thing they would have done, popped the socket front off and connected to the diagnostic test point, they would have seen instantly if you had NO line connection.

My cable was originally Orange on A, and White on B, that was how the engineer wired it probably 42 + years ago, as i have been here that time.... Can look at the cable if you wish, dead and buried now on Fibre but the cable is still hanging in the cupboard...

Re: Master Socket 5C MK4 wiring

JimM11 — Sun, 04 May 2025 16:27:07 GMT

@Rooster295 Take the picture back off the router, and connection to your master socket, attach and post them up.

Re: Master Socket 5C MK4 wiring

Rooster295 — Sun, 04 May 2025 16:59:18 GMT

Thanks for your reply.

The first visit was them just making sure I had set up router correctly I.e the plug was in the right section, the broadband socket was in the right bit.

The second visit he took the faceplate off (but didn't do any sort of test) and replaced the face plate I had with a newer one.

I do have Openreach coming but the appointment isn't until Friday and I was just anxious that if they can't do anything on Friday it will ne another week/week and a half. I have been told I am going to be compensated.

I'll post pictures when I'm home.

Once again, thanks for the reply.

Re: Master Socket 5C MK4 wiring

JimM11 — Sun, 04 May 2025 18:06:26 GMT

@Rooster295 Took a quick look, the cable from pole to home, has orange/white/green/black for it, the A/B does not matter what the colours are used or even which one goes where, it does matter that 2 cores from the pole are the same used either end, and the pole goes back eventually to the green street cabinet what ever pair that OR use. With the latest equipment that is being used there is no way that you can check, so down to the engineer visit to hang a tester on your line and check out the pair all the way back to the connection point. It's not rocket science for the telecom engineers, they will have done it many many times before unless the cable is stuffed somewhere and an engineer robbed a pair to get someone else up and running, that does happen but not in your home, that's for sure....

Re: Master Socket 5C MK4 wiring

XRaySpeX — Sun, 04 May 2025 18:13:14 GMT

@JimM11 wrote:

the cable from pole to home, has orange/white/green/black for it, the A/B does not matter what the colours are used or even which one goes where

It must matter! They are 2 separate individual landlines (even if inactive). You must pair them up, either orange/white (Pair #2) or green/black (pair #13).

Re: Master Socket 5C MK4 wiring

JimM11 — Sun, 04 May 2025 18:58:07 GMT

Where did you get that from?

Re: Master Socket 5C MK4 wiring

Mustrum — Sun, 04 May 2025 19:46:49 GMT

@XRaySpeX wrote:

@JimM11 wrote:

the cable from pole to home, has orange/white/green/black for it, the A/B does not matter what the colours are used or even which one goes where

It must matter! They are 2 separate individual landlines (even if inactive). You must pair them up, either orange/white (Pair #2) or green/black (pair #13).

Jim's statement is correct.

Much will depend on the cable from the external junction box to the master socket. Often if installed by formal telecom trained installers it will be 6 core, but only one pair will be used, old school will follow the colour code and use blue white/white blue, but it matters not, as long as you use the same pair at both ends of the cables.

As for two lines, that really depends if there is a spare line circuit available. However not something to rely on, also depends on the cable used to connect to the house. In many cases one 6 cable is used to service more than one house.

Re: Master Socket 5C MK4 wiring

JimM11 — Sun, 04 May 2025 20:35:28 GMT

@Mustrum I will strip a little back tomorrow and have a look see if the twisted pairs can be ID and let you know what is in that 4 core cable not in use any more.👌

Re: Master Socket 5C MK4 wiring

XRaySpeX — Sun, 04 May 2025 21:17:59 GMT

Not quite!

@Mustrum wrote:
it matters not, as long as you use the same pair at both ends of the cables.

But you, the user, will never know the wiring arrangement at the other end, pole or underground, so you can only go by the standard pairing or else end up with cross-wires.

As for pairs of lines, many residential homes often have a pair of lines coming in with most only making use of 1 of them. However I do have have such a pair, both of which were live & active some period in the past. I never asked for 2 lines in the beginning but they were already there when I wanted a 2nd line. As you say for all I know there might be a 3rd present but I've never needed to find out. I have never implied anyone should rely on having 2 lines but was commenting on @JimM11 's specific arrangement of having 4 cores.

Re: Master Socket 5C MK4 wiring

XRaySpeX — Sun, 04 May 2025 21:16:45 GMT

@JimM11 : From you said of having 4 cores.

Re: Master Socket 5C MK4 wiring

Mustrum — Sun, 04 May 2025 22:11:41 GMT

@XRaySpeX Any wiring up to the Master socket is the responsibility of Openreach.

Really not sure what you are trying to say?

Your particular circumstances are just that. Have a look at party lines when lines were in short supply.

Not sure how you are trying to help the OP?

Colours are irrelevant, what you have also,

Re: Master Socket 5C MK4 wiring

XRaySpeX — Sun, 04 May 2025 22:45:16 GMT

I'm just saying to the OP that the wiring coming to the A & B terminals should be as the schema of Pairs that I posted as we can't know what the arrangement is as the other end, albeit that the A & B colours can be reversed as it is DC.

Then got side-tracked by @JimM11's & my specific arrangements for multi-pairs where it was alleged that it didn't matter which pair of wires were employed. The latter I disagree with.

Re: Master Socket 5C MK4 wiring

Mustrum — Sun, 04 May 2025 23:04:06 GMT

@XRaySpeX wrote:

I'm just saying to the OP that the wiring coming to the A & B terminals should be as the schema of Pairs that I posted as we can't know what the arrangement is as the other end, albeit that the A & B colours can be reversed as it is DC.

Then got side-tracked by @JimM11's & my specific arrangements for multi-pairs where it was alleged that it didn't matter which pair of wires were employed. The latter I disagree with.

OK, so wrong on both counts.

Point 1, you don't know what the connection is at the other end of the A & B

Point 2 why, so many times you attack people who clearly know more about stuff on here than you do, but you lack the technical knowledge>

Re: Master Socket 5C MK4 wiring

Mustrum — Sun, 04 May 2025 23:07:51 GMT

@Mustrum wrote:

@XRaySpeX wrote:

I'm just saying to the OP that the wiring coming to the A & B terminals should be as the schema of Pairs that I posted as we can't know what the arrangement is as the other end, albeit that the A & B colours can be reversed as it is DC.

Then got side-tracked by @JimM11's & my specific arrangements for multi-pairs where it was alleged that it didn't matter which pair of wires were employed. The latter I disagree with.

OK, so wrong on both counts.

Point 1, you don't know what the connection is at the other end of the A & B

Point 2 why, so many times you attack people who clearly know more about stuff on here than you do, but you lack the technical knowledge>

Update before edits.

Re: Master Socket 5C MK4 wiring

XRaySpeX — Sun, 04 May 2025 23:54:26 GMT

@Mustrum : Where I have I attacked peeps? It is you that is attacking most vehemently.

It is a moot point who is more knowledgeable. Are you saying you are infallible & know more than anyone else?

This is a forum where we all should all get our say.

Your points make no sense.

Why are you so aggressive?

Re: Master Socket 5C MK4 wiring

WillKirk — Mon, 05 May 2025 00:04:04 GMT

From what I remember, average phone line will have 4 wires. Blue and white/blue are used traditionally as primary, Orange and White/Orange traditionally used as secondary (might have gotten the colours wrong here but I don’t think so. There is a Blue ‘pair’ and an Orange ‘pair’ either way)

When I say traditionally I mean by BT/Openreach over the years once they changed over to System X and new wiring in the 80s.

Phone line will only use the Blue pair and the Orange pair is snipped back and ignored ‘unless’ a second phone line is used or the Blue pair has a fault and instead of exchanging the cable to the house they just use the other pair which is presumably good.

So, point being your A and B will be a Blue Pair unless it’s not and it’s an Orange pair. This is located at the very back of the socket plate and yes, is property of Openreach but hey… sometimes you just need to look for decorating purposes, right?

This differs from your standard (Cat 3 I think?) telephone cable which is used for extensions and can be 4 or 6 wire all depending what you buy and is a multitude all depending on if you got solid core or stranded. It should be solid core, but as the internal extensions are the customer’s jurisdiction who knows what you’ll find. Some people use Cat5/5E/6.

Anyway. If an Openreach engineer came out to you, then they usually know whether the line is working or not before they get to your house as they stopped off at the local cabinet and/or Exchange and tested. If they need to they will test from the house.

If it was an EE Engineer not Openreach — no ideas who they are but they aren’t engineers by what I have heard, and they are hardly functioning adults by what I have heard… so make sure they are Openreach or and Openreach contractor and not Geek Squad or whatever the heck they call themselves and BT and EE employ.

as for not knowing what comes into the property that’s not entirely true as the A and B on master socket will line up with what is on the other end… because as far as I can remember it actually makes no difference which way round they go. You can put them on the wrong way round and they will still work as they router works out which is which out of pin 2 and 5, which is send and receive. And if the customer has a small junction box on the windowsill like I do, a hangover from the old GPO 746 days, then you can see what wires come from the pole/ground to the internal wiring as well. If not then the Master Socket is normally on an outside wall and therefore is wired directly.

not sure what all the arguing is about. The answer is no, it is unlikely is it wired up wrong unless you let the cowboys at it. Have Openreach out specifically to test the line is necessary. But it’s more likely that something else is wrong, if anything actually is.

Re: Master Socket 5C MK4 wiring

Rooster295 — Mon, 05 May 2025 10:05:49 GMT

Thank you

I have unscrewed and not touched anything but that is how it is set up.

Four cables. Blue (no white) in A and Red in B. Green and brown just dangling there.

I am in no way an expert and feel I will have to leave this until Friday when openreach come.

This is the only phone socket in house.

Re: Master Socket 5C MK4 wiring

JimM11 — Mon, 05 May 2025 12:08:31 GMT

@Rooster295 Should be good, just screw it back on the wall plate, your Router RJ11 is also plugged in the correct L/H side socket, so it's all good to go on the Master Socket side. OR will check out if the find the line is inactive or disconnected somewhere. Hope it all goes as planned.👍