Short version - with an NTE5c and a mk4 faceplate, you have the option of wiring a phone-only extension from the 2/3/5 points behind the removable faceplate. If you only wire 2 and 5, are the phone-only extensions still filtered properly, without the need for separate micro filters?
Modern wisdom suggests 3 (the bell wire) isn't required and can induce noise on the line. However, a friend's connection, which I helped rewire, was struggling for speed after moving to BT Infinity fibre. He's put up with it for 18 months, was on the cusp of ringing BT, before I suggested he tried the test socket. Low and behold, it's gone from 27mbps to 45mbps.
I then suggested plugging the telephone (the only device plugged into the system, other than the BT Hub) back into it's extension via a microfilter. The speed boost seems to have stayed there.
So I'm left wondering if me not wiring from 3 on the NTE5c to the extension socket, has caused this issue/means it's not being fully filtered? I watched an informative YouTube teardown video of an NTE5c that explains how the extension wiring is isolated/activated by the faceplate. I know that by using 2 and 5, there will be no VDSL signal present at the extension, but is all other necessary filtering still performed without 3 being connected?
On an NTE5a, I know the extensions were taken from the back of the faceplate itself, which presumably makes a difference to how the filtering would/wouldn't work. Most of the posts I can find online relate to this earlier setup and not the NTE5c/mk4 faceplate.
Thank you for any help/reassurance in advance.
I have the NTE5C & MK4 faceplate with exactly the same wiring configuration you have and adding a filter to the extension socket makes no difference. I just tried it without any improvement 😞
Pin 3 has absolutely no bearing on filtering and is not required to be connected.
Thanks everyone. I guess the only plausible thing then is a faulty mk4 faceplate? Having watched the disassembly video, there are some components within the NTE5c but the main filtering comes via the faceplate.
With regards the PDF linked, that shows to connect wire 3?