Roberto,

Your statement The reason being that the newer VDSL2 filter plate is to a higher spec and removes a wider range of noise spectrum from the phone wiring side being fed back onto the line could be misconstrued by some readers of this topic. I certainly was, at first reading. This is because it depends on precisely what you mean in that statement by "the line".

You see, out of curiosity I recently took apart a new Mk3 Openreach intermediate plate and, inspecting it very carefully, was surprised by one particular feature of the filtering. What I found was that the prior unfiltered connections going to both the user-usable AB IDC connection on this plate and the two centre pin connections of the shuttered RJ45/RJ11 outlet on the top face of the plate, ie. the connections to the modem, now go instead via a small choke (inductor).

The choke is effectively in series with the modem connection; it's made from extremely fine wire. It's in fact a double-choke, one bit for the A side, the other bit for the B (to keep the arrangement balanced). So, with this Mk3 plate, the xDSL modem no longer connects directly to "the line", ie. to the AB drop-line coming into the premises. Instead, the modem connection is filtered.

Perhaps I'm just stating what most contributors here already know, but for me this is a new departure as regards the overall filtering, and it's presumably designed to reduce any very high-frequency noise that gets picked up on the AB drop-line connection on the back of the NTE5 from getting through to the modem. Clearly, the value of that inductance has had to be assessed very carefully so as not to unduly affect the HF performance of the xDSL going to the modem. This new bit of filtering would also curb any HF noise coming back through and on to the AB line from the phone's ring-wire connection (which may or may not already be filtered, depending on which issue of NTE5 lower-half you happen to have, ie. whether or not the lower plug-in half of the NTE5 incorporates a series choke on the pin3 connection).

Essentially, this means that if you choose to use a Mk3 intermediate plate, then beside it incorporating sophisticated filtering for the connection of one or more phones, the connection to the modem (whether via the RJ11 port or the user-accessible IDC connection) now also has a modicum of filtering applied to it.

On the matter of the separate filtering for the pin3 ring connection, I fail to understand why Openreach don't declare it as redundant. What with the huge takeup of mobile phones in the last decade and decreasing numbers of landline-phone users being around (I'm one), and in any event most landline phones these days incorporating self-generation of the ring tone and therefore not needing the pin3 ring connection, one would have thought that Openreach would have by now eliminated completely this outdated ring connection. By doing so, they'd not only solve the "ring noise" issue at a stroke but would also save a bit on the cost of producing the NTE5 lower-half. This would seem especially so, given that they've even realised that the NTE5's surge arrestor (over-voltage proector) has limited usefulness and that, on newer NTE5s, is now being omitted.

Even if the phone itself doesn't carry through the pin3 connection and make use of it, the ring-wire connection between the NTE5 and the phone - regardless of whether that includes a choke - will still act as a considerable aerial for the picking up of EMI and coupling it into the AB dropline termination. This, after all, is what we've all appreciated for a considerable time. The more practical of us might be inclined to take apart the NTE5's lower half and actually cut the printed circuit where it meets the pin3. This would then absolutely ensure that the NTE5-to-phone pin3 connection couldn't have any detrimental effect. Although this would be disapproved of, I suppose it'd be okay if one were to keep a spare, undoctored NTE5 lower-half to hand, so that the situation could be restored if, say, one moved house.

Incidentally, I took photos of the front and rear of the MK3's intermediate plate's circuitboard, so that I could put the plate back together again and could then study the images at leisure. (I recall seeing similar pictures posted elsewhere in a different topic in these forums, but annoyingly have not been able to find that topic again). Initially, I was astonished to find that the modem's AB connection was now filtered. Hitherto, it'd always been considered sacrilege to do so.

I guess you already know all of this, though. After all, you're a seasoned and well-informed contributor to these forums. But I thought I'd just mention in a bit of detail what I'd discovered, so that others can perhaps appreciate how the NTE5 and its add-ons are continuing to evolve as regards filtering.

Is that the REIN filter? I believe the lightning surge gap has been removed also.

Just to make it clear: the filtering of the modem connection to which I've referred is done inside the Mk3 intermediate plate; it's done on the plate's internal circuitboard. Any filtering of the ring connection to the phone, if present, is done inside the plug-in lower-half of the NTE5. The main body of the NTE5 has the standard 470K-ohm resistor and the 1.8uF capacitor and normally has a surge arrestor too (going effectively between the dropline A and B wires), but recent NTE5s tend now to omit the surge arrestor. Indeed, I took apart a spare NTE5 that I decided to buy recently and found it had no surge arrestor (traditionally, this has sometimes been referred to as the 'spark-gap component', but I think that's a rather outdated term now). Others in these various forums have found similar.

Addendum: if you feel a bit unsure about using a Mk3 plate because of this, there's always the option of using a Clarity plug-in faceplate or an ADSL Nation faceplate instead. The Clarity one is less easy to get hold of now. I've tried both the Clarity device and the ADSL Nation one in the past and found the Clarity one the better and more electrically robust of the two (although employing extensive filtering for the attachment of phones, the Clarity and the ADSL Nation work in slightly different ways). For the past several years I've had the Clarity one in use. At present I've no idea whether either apply any filtering to the modem connection, though. Considering their design ages, I'd think not.

Edited by deleted (Tue 12-Jul-16 14:33:58)

On VDSL?

What question are you asking? If it's something along the lines of 'Does all of this apply to VDSL as well as ADSL?' the answer is firmly Yes. The extra filtering is obviously designed to benefit both, but particularly VDSL.

Although the Clarity and ADSL Nation faceplates were first designed and made available in pre-VDSL days, they can still be used successfully for VDSL, and contributors like Roberto have already alluded to that. The difference in resultant DSL performance between either of the aforementioned faceplates and a Mk3 intermediate plate is going to be marginal, in my view. 'Ya pays ya money and ya takes ya choice'. The recent additional filtering provided by the Mk3 plate will, I believe, benefit only those copper lines (ADSL and VDSL) that happen to be affected by spurious HF noise. It'll also assist in reducing/further reducing any unwanted ring-wire HF noise that gets coupled on to the AB line inside the NTE5 via the 1.8uF capacitor.

Are you using these filters with ADSL or VDSL?

The Openreach MK3 faceplate works well with both ADSL and VDSL. I installed mine whilst I still had ADSL (limited to 8down 0.4 up) and it was rock solid.

Recently made the switch to VDSL and my current connection stats via the MK3 plate are:

Upstream Downstream
Current Rate(kbps) 19999 79987
Max Rate(kbps) 36029 126406
SNR Margin(dB) 23.3 19.4
Line Attenuation(dB) 0 10.4

Speedtest.net gives result of 74.89 Mbps down, 18.89 Mbps up, Ping 16

Have tested the connection speed through the day and it's very consistent, probably helped by using an Independent ISP as well as the FTTC cabinets being very recently installed into the village. I doubt many people have subscribed to the service yet.

As explained a few sentences back, I'm using a Clarity faceplate at present - but on ADSL, as it happens; at the moment it's not worth me upgrading my DSL service to VDSL. I bought a Mk3 intermediate plate recently (and at the same time a complete spare NTE5) to have to hand in case I move house this year, in which case I'd opt for VDSL at the new address. The two spare devices have given me an opportunity to take them apart and explore the filtering.

I've not come across any scathing reviews of the Openreach Mk3 plate. I gather that it works very well, on both ADSL and VDSL services. But given that the NTE5 main body is a permanent and BT-owned component that stays in place, it's a fairly easy exercise to switch between using a Clarity plate, an OR Mk3 plate + lower half, and an ADSL Nation faceplate, if you wish to experiment.

I didn't think you are on VDSL. This thread is about VDSL.

Very interesting report on the MK.3 thanks for that.