Master Socket question

Hi, I wonder if anyone can help answer this for me?
I'm on FTTC, with about 500m of old phone line from the cabinet to the NTE5a master socket in my house.
I've been having some trouble with disconnects, so I've been running some tests to see if any of them are coming from my internal wiring.

But there's something that I don't understand:
1) If I plug into the master socket (i.e. faceplate removed), then I get a speed of 38+ Mbps.
2)But if I put the faceplate back in and plug into the faceplate, the speed drops by 10Mbps.

There is one extension wired into the back of the faceplate (connected via the blue and the white/blue only. i.e. the orange bell wire is NOT connected);

But here's my puzzle - I suspected that the extension was somehow causing the drop in speed - if I disconnect the extension wires, the speed is back to 38 at the faceplate.
BUT, when I then fitted a new cable & extension socket in place of the old, the same drop in speed occurs at the faceplate.

To be double sure, I bought a new master socket and fitted it anyway, and the result is exactly the same - 38 from the master socket, but only 28 from the faceplate, even when new extension wires are fitted.

(description edited as I initially described it wrongly).

Can anyone please tell me, Is this normal? (and why?) Or if it's not normal, then what else could cause this?

Thank you for any help with this

Edited by alfiecat (Wed 23-Feb-22 07:36:08)

Was it just the master socket face plate that you changed or did you change the bit behind as well?

Hi, I replaced both parts.

But stupidly, I have made an error in my description of what is happening. I've edited the original post, but I will describe it again here :

In the test socket with faceplate removed, speed is 38.
With the faceplate back in place & router plugged into faceplate, the speed is down to 28.
If I remove the internal wiring, and plug into faceplate, speed is back up to 38. OK so far.
So I assumed the internal wiring is at fault.

Just to be extra sure, I decided to eliminate the master socket as the cause, by replacing it (both parts). This gave the same results as above.

Then I bought some new 1308 cable, and connected a new makeshift extension (15 metres) to the back of the faceplate, in place of my extension wiring.

The speed at the faceplate was once again back down to 28.

So, even with new wiring to an extension, the speed drops to 28.

But, if I plug the router into the extension itself, I get 38 again.

So, is the presence of extension cable (new or old) enough to cause that sort of drop, or is it faulty wire / connection somewhere?

Thank you again

So, in short, the extension works ok, but the speed at the master faceplate is always down by 10Mbps.

Edited by alfiecat (Wed 23-Feb-22 07:36:50)

When testing at the master socket did you leave a filter plugged into the extension socket to properly terminate it?

No I didn't, as there was nothing plugged into the extension socket when I was testing. Does it need one even if no device is plugged into the extension socket? i.e. do I need to just plug a filter in the extension with nothing attached?

Thanks

Edited by alfiecat (Wed 23-Feb-22 12:51:47)

Ideally it should be terminated with a filter even if noting is connected, otherwise you have two open wires potentially acting as antenna.

If you are not using an integral faceplate filter at the master socket any extension wiring appears as a bridge tap and is generally detrimental. Whilst installing filters at the far end of any extension wiring allows the extensions to be used for voice it does nothing to prevent reflections of the higher frequencies used by VDSL.

For the NTE5A use a MK3 filter faceplate, or for the newer NTE5C a MK4 filter faceplate.

In reply to a post by alfiecat:

But, if I plug the router into the extension itself, I get 38 again.

You are obviously not using a filtered faceplate. If you wish to continue using a voice extension it would be preferable to get a filtered faceplate as tdw42 suggests.

Thanks very much to all of you for the very helpful replies.
I thought I had bought a filtered faceplate when I replaced the master socket, but must have been wrong. Never mind, I will take a look at a MK3 faceplate, but I think I might opt to rearrange my devices, do away with the extension cable altogether & keep the router & phone at the master socket. I'll then use an ethernet extension from the router, through the wall, to my pc instead of using the telephone extension.

(I've been using a temporary ethernet extension to the pc while doing these tests and it gives me full speed, so I'll fit a permanent one in place).

Thanks again, your help is much appreciated.

If you got a MK3 faceplate you could connect 100% copper cw1308 cable (or cat5e) to it's A&B terminals and run that unfiltered feed through to a dedicated rj11 socket in the other room. The router could then be connected to that socket via a rj11 cable. If you did that it would still be possible to use a filtered voice extension from the NTE5a/MK3 to a phone connected to the original phone socket in that room.

However if you are happy not to have a voice extension in the other room then I'm sure a NTE5a plus a micro filter connected to the router then ethernet to the computer in the other room will be OK

Good luck.