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Confused about master socket and test socket

mseries
Grafter
Posts: 37
Registered: 25-12-2010

Confused about master socket and test socket

I have been asked to plug my router into the test socket, which i will do when I get a chance. I am wondering though what actually is the difference between the test socket  and the socket on the front of the face plate. My home has only one phone point, the master socket, all extensions are plug in ones from there, my microfilter plugs into the master socket and my phone extension plugs into the microfilter alongside my modem/router. There are no other extensions hard wired into this socket. Now I have a broadband fault at present and I have reproduced it with no phones plug in. Only my microfilter and modem/router, so what happens between the test socket and the socket on the front of the face plate ? My socket was fited by BT about 20 years ago.
and finally a question will my phone still work if I plug it into the test socket (via or not via the microfilter) ?
4 REPLIES
cajef
Grafter
Posts: 208
Registered: 20-07-2007

Re: Confused about master socket and test socket

All you are doing by removing the faceplate and plugging into the test socket is isolating any internal wiring that may be connected to extension sockets, if you don't have any extensions then all it would do is prove whether the faceplate is faulty, using the test socket is just the same as plugging into any other socket so your phone works as normal.
Community Veteran
Posts: 19,099
Thanks: 434
Fixes: 21
Registered: 31-08-2007

Re: Confused about master socket and test socket

Here is a Test Socket picture.
If you don't have a Master Socket similar to the one on the left, then reply to the fault ticket saying you only have the one socket and you've been told it's not the latest NTE5A type.
Edit: In your normal setup as long as there are no extension leads between the socket and the filter that shouldn't give you any problem. In other words the extension lead is for the phone only plugged into the filter to be clear.
JHK
Newbie
Posts: 1
Registered: 08-10-2017

Re: Confused about master socket and test socket


cajef wrote:
All you are doing by removing the faceplate and plugging into the test socket is isolating any internal wiring that may be connected to extension sockets, if you don't have any extensions then all it would do is prove whether the faceplate is faulty, using the test socket is just the same as plugging into any other socket so your phone works as normal.

Although I have been told the same by more than one technician I do not see how this can be the case. Apart from it being a logically pointless exercise in the absence of any extension sockets connected to the master, I have just inspected an old unused master socket and found it to have an internal circuit board with components on (looks like a capacitor, a resistor and a diode). Surely this circuitry performs some functionality for good reason? A little concerned due to the fact that a Plusnet technician instructed me to connect to the test port for a week or two and never got back to me. Just discovered that I have been connected like this for a very long time now! My guess would be that at the very least, the functionality of the PCB is something to do with surge suppression (protection from voltage spikes down the line )

Community Veteran
Posts: 4,916
Thanks: 335
Fixes: 16
Registered: 10-06-2010

Re: Confused about master socket and test socket

I think the components in the master socket are still connected to the incoming line when you've exposed the test socket. They form the proper termination of the line, and create the ringing signal on the bell wire (which is not required by most modern telephones). Surge protection components were removed from the master socket designs a while ago because they are detrimental to broadband performance.

I think the only components in the removable lower front portion of the NTE5A are for an interference filter on the bell wire.