'BT Mark3 filtered faceplate' from Ebay

[#1]

Bought one of these a week ago, sold as a genuine BT product, but having set aside my rat-tail ADSL filters for the phones and extension I was disappointed to find that my phone line had developed a pronounced hum (more noticeable when performing the quiet line test of course.)
Prior to this I had the standard (unfiltered) faceplate and used two ADSL filters in series (ADSL plugged into first one  ;)) and phone line was completely quiet.
I've had to put a single filter back to get rid of the noise (a DECT phone and an extension to upstairs are taken from that via a splitter.)
Not happy of course - I wasn't expecting any miracles from it but I at least expected to be able to do away with the unsightly filters.
No noticeable effects one way or the other on broadband errors/rates/attenuation etc.
I've attached a picture (which rather shows up the age of the NTE5  ::)) - is there anything about the logo which suggests 'fake' to you, or am I not alone in finding the filtering inadequate on this device?

[#2]

Looks genuine - see this one http://www.amazon.co.uk/GENUINE-BT-Openreach-Interstitial-Compatible-White/dp/B00NMUXPOS

[#3]

I have the fttc faceplate in my lounge, 30 minutes after the engineer left from installing it I put in the old adsl filters to stop the problem of buzzing and ppp session drops every time the phone was picked up, I don't know why but I read somewhere that it was a common problem with unfiltered phones sending and receiving harmonic signals into the line when operated hence the buzz and ppp session drops
maybe its down to the phone being used maybe not /

[#4]

Thanks Jim - just checked inside the lower cover and it bears similar UK reference numbers, so it is probably genuine, but possibly there's another reason for it being not much more than half the price of the Amazon offering. 
Nanotm - well, that's a considerably worse scenario, especially as I thought the whole idea was to ensure that the phone circuits can't feed interference into the ADSL signal
Will wait to see whether anyone else has found it wanting in the phone filtering department....

[#5]

There's quite a few people that have them and this thread is the first I've spotted where there've been issues. Very odd.

[#6]

I seem to be specialising in unusual issues recently AO - hopefully it's just a temporary phase. 

[#7]

As mentioned in your other thread that you've linked here, as you've had a refund, then other than trying another from a different source, difficult to come to conclusions.

[#8]

A new BT Mk3 filtered faceplate was fitted by a OR engineer a few weeks ago (I'd taken the 'faulty' one off hoping he'd do just that) and I still found there was a slight hiss on the corded phone at the end of an extension during the quiet line test.
The extension is connected to the front plate via a splitter, the other phone being a DECT phone/answering machine. The hiss is there even when the corded phone is connected directly to the face plate with the DECT phone unplugged from the mains.
An additional ADSL filter does remove the noise completely.
I've seen a recommendation to double-filter DECT phones before, but not when a BT filtered face plate is being used.
Just thought I'd post this in case it helps anyone who is not quite sure whether their line is passing or failing the quiet line test.

[#9]

The Mk3 BT filtered face-plate is nothing more than a better quality filter whose design has been optimised to work well with vDSL and still give good common-mode rejection because of the added common-mode filter. The attenuation that the filter gives to unwanted frequencies will not be significantly better than other good quality filters.
The benefit of double-filtering DECTs etc, is that it does add significant further attenuation to those unwanted frequencies passing in either direction.
Note that the primary purpose of these filters is to prevent the phone circuitry having an undesirable effect on the broadband signal as well as the secondary benefit of broadband signals giving some noise on poorer designed phones circuits. Some modern phones will exhibit a very slight hiss anyway because of the use of cheap semiconductor devices.
So yes, no reason not to double filter even with a Mk3 Filtered plate, if it improves performance/noise of either broadband and/or phone.