Which is my master socket?

[#1]

I have two NT5 type sockets in my house. Is there any way to test these to establish which is the master (or if they both are).

[#2]

First thing would be how do the phone line physically get to your house? i.e. can you see the cables externally? If so, the the master is likely to be the one nearest the external cables.

If like mine, the phone lines are underground but have a external wall mounted access plate, then the master phone will probably be inside the house behind the wall plate.

[#3]

The incoming line is underground, but appears outside near the meter cupboard where it connects to the house via a junction box. From there, the cable disappears into the wall, so I have idea which of the the two 'master' sockets it goes to first. That's why I'm wondering if there is any way to test which is which.

[#4]

If you are lucky then the non master may only have 2 wires connected coming in see http://www.kitz.co.uk/adsl/socket.htm for a two wired extension NT5 installation with photos .

[#5]

You could always undo the two screws on each socket and look at what is inside, the master socket will have a few extra components on it. the slave will probably only have one set of wires.

[#6 · Accepted solution]

Remove the lower front plate from both NTE5 sockets, and see which one has a dial tone in its test socket. If both sockets still work, then you probably have star wiring, which is not ideal or can be problematic for broadband.

If one socket has been wired to the other like an extension socket, it will be wired to the removable front part of the other socket, so you'll disconnect it when you remove the front plate of the first socket.

You shouldn't really have two NTE5s or other master-type sockets connected to the line anyway. I don't think there are any non-master type NTE5 sockets.

All NTE5 sockets will only have two wires connected to the back of them, there are only terminals for two wires at the back of an NTE5.

[#7]

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@ejs wrote:

Remove the lower front plate from both NTE5 sockets, and see which one has a dial tone in its test socket. If both sockets still work, then you probably have star wiring, which is not ideal or can be problematic for broadband.

I checked both sockets. With both lower front plates removed, I can connect a phone to either of the test sockets and get a dial tone, which I assume means it is star wiring. This has not caused any problem with my existing broadband connection, but I'm being upgraded to fibre on Monday, so I'll have to wait and see what happens then.

[#8]

Unfortunately, I think bad wiring can have a greater adverse effect on FTTC (well, on the VDSL2 signals going over your telephone line between the cabinet and your home). Star wiring, and even other extension wiring not filtered centrally, acts as a "bridged tap", which is one of the things mentioned on the Broadband Availability Checker which could cause you to get speeds in the B range instead of the A range.

[#9]

If all goes according to plan, my fibre broadband service should be connected on Monday. As soon as this is live I will run speed tests and then post the results here.

At present, using standard broadband, I'm getting 12.7Mbps, which isn't bad for the area where I live.

[#10]

There are a number of different socket types - see here https://portal.plus.net/support/broadband/master-socket-guide.shtml

It is possible that someone has in the past added a second phone extension to the line and not used the right (non-master) socket.  You might need to replace a second master socket with a proper slave / extension socket.

The master socket acts as the BTOR service boundary point: everything up to the master socket is BTOR's responsibility, everything after it is your responsibility.  If there are only two sockets in your home, the extension socket will only have one wire in / to it.  If there are more than two sockets, no socket should have more than two cables to it - one in, one out.

If wired to the latest standard, the master socket will have the incoming wires attached to the back plate and the extensions will be attached to the removable lower face plate.

See here for illustrations of master and non-master sockets and how to wire them - http://www.wppltd.demon.co.uk/WPP/Wiring/UK_telephone/uk_telephone.html

[#11]

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@Townman wrote:

There are a number of different socket types - see here https://portal.plus.net/support/broadband/master-socket-guide.shtml

It is possible that someone has in the past added a second phone extension to the line and not used the right (non-master) socket.  You might need to replace a second master socket with a proper slave / extension socket.

Thanks for the info Townman.

As I mentioned in an earlier post, both the sockets are connected directly to the incoming line and both appear to be master sockets.

The house is very old (200 years) and was converted from a storage warehouse some fifty years ago, so the phone wiring is something of a mystery. There is no easy access to trace the route of the incoming line, although I have located a (disconnected) cable which runs from one of the 'master' sockets to several other outlets throughout the house which are unused currently.

Both of the 'master' sockets are in use however, but since they are quite remote from one-another rewiring is a problem.

As I said previously, BT should be connecting the fibre service tomorrow (Monday), so my plan is to wait and see what sort of line speed I get once this is up and working. I assume that to get a proper idea of line speed I will need to wait a few days until the exchange adjusts things for the new connection.

[#12]

Hmmm... there is the possibility that these are two different lines!  Coming in on the same cable 'bundle' but using different pairs.

Do you have two phones?  If yes, plug a phone in to each socket dial 17070 on one phone, pick up the other - do you hear a dial tone of do you hear the test service announcement as on the first pone?

If you hear a dial tone, dial 17070 and note the service (phone) number reported back by the automated service.

[#13]

Moderator's note by Mike (Mav)
I have reset the fix to ejs

[#14]

OK. BT have done their stuff and the upgrade is complete.

I checked the sockets as suggested and they are both connected to the same incoming line.

Everything is working, with one puzzling exception. Checking the Plusnet Hub Manager, I see a downstream speed of just under 30MBps at the router (the maximum speed advised by Plusnet. However, using brand new TP-Link Ethernet/WiFi powerline extenders I am only seeing around 8-10Mbps downstream (measured using the BT Wholesale speed test) on PC's using the Ethernet connection and about the same speed on wireless devices, even when standing right next to the router. Conversely, the upstream speed is running at just below 2Mbps, the maximum achievable.

BT advises that it can take several days for the new line to achieve its maximum speed, but if the router reports that the line is providing close to 30MBps, what is causing such significant degradation? 

Bear in mind that my previous non-fibre broadband was giving me over 12Mbps, so whilst I would expect some loss through the Powerline ethernet, it is clearly not this which is causing the slow-down.

[#15]

Probably what you need to do is check your Plusnet Current Line Speed at https://portal.plus.net/my.html?action=data_transfer_speed

If it's still the same as what it was when you were on standard broadband, that'll be the reason for the slow download speeds. You can contact Plusnet by live chat, phone, or wait until someone at Plusnet reads the forum, and they can update your Current Line Speed (or it should update automatically, eventually).

As you achieving your estimated speed, it may be that you're largely getting away with the dubious wiring arrangement. However, I think Plusnet should be giving their estimates from the B range, so it may be that you're getting speeds in the B range rather than the A range due to your wiring. It's also possible that the wiring could be causing more of a problem than is immediately obvious, in which case your speed will fall over the next few days or weeks.