Line Attenuation

[#1]

that is definitely where Boreham Village is, the Airfield is about 2 mile North

[#2]

Quote from: James_G

The T symbol is the mark of ownership by BT and is the demarcation point/master socket. It was replaced by the piper branding when BT rebranded, and then subsequently by 'Openreach' branding now.

According to Wikipedia, BT used the 'T' logo between 1980 & 1991 then the 'Piper' logo from 1991 to 2003.  Thereafter they used their current 'Connected World' logo.  Telephone sockets were introduced in 1981 to give you the opportunity to buy your own phone.  Prior to that, all phones were rented from BT, installed by BT and wired into a junction box.
The most common form of BT Master Socket is the NT5E.  This has a detachable faceplate (to which your internal wiring should be connected).  In fact it is so common that the 'Fault repairs...' section at the beginning of the BT 'Phone Book' (telephone directory)  illustrates this socket and how to remove the face plate to access the test socket behind it.  Most of the ones I see bear the 'T' logo, which I presume indicates they were fitted before 1991.
I don't recall ever seeing a master socket bearing the 'T' logo that was not an NT5E type before.  What do you all have at home?  Does anyone know the rules which governed what socket was fitted?

[#3]

It might also be the model of Router in use.
I get 1.7 Mbps with a Netgear DG834G v4, but 1.9Mbps with a netgear DG834G v3.  My ancient Draytek router can only manage 1.1Mbps, and all these are in the same master socket.  (I live 5 miles from the exchange).

[#4]

Quote from: ReedRichards

I don't recall ever seeing a master socket bearing the 'T' logo that was not an NT5E type before.  What do you all have at home?  Does anyone know the rules which governed what socket was fitted?

Two mistakes.
Firstly, quoting a Wikipedia article as it if was authorative, and secondly assuming that because you haven't seen something, it doesn't exist.

Evidence of both 'in the wild' if you will, basically one of the earliest UK master sockets, and the latest, which includes 'i-plate functionality'

[#5]

Quote from: ReedRichards

I don't recall ever seeing a master socket bearing the 'T' logo that was not an NT5E type before.  What do you all have at home?  Does anyone know the rules which governed what socket was fitted?

Thats exactly what I have - the old T logo socket and it's the small 68mm 1 piece socket (NT5E are 88x88m in size) so no i-plate option for me i've gotta open it up and disconnect the bell wire.
And not that it's any consolation to you but i've just found out im 1.49km from my exchange (direct) and im on the pro package (went live 2 weeks ago) and i've had 1 instance of 1.1mb download speed but now seems to be stuck at 900k and on a few occasions i've seen 400k.... It's not plusnet faults by the look of things so now i've got to go do some in-depth testing as iv'e done the basics (filters/router reset etc)... Sounds like you've already done a fair but yourself but guess it's something you just have to keep plugging away at until you find the cause of the problem. G'luck.

[#6]

James_G, I don't regard anything I read on the internet as authoratitive, even your comments.  But your pictures are appreciated.  I had read that the latest sockets include i-plate functionality (but that was on the internet so I didn't know whether to believe it or not).  My impression is that the non NT5E-type master sockets are uncommon but they clearly do exist (commiserations to robbiegy2k).  What I'm more curious about is the rationale BT would have had for installing them. 

[#7]

Very simply - if, when the socket was installed, there were no other sockets in the property then there would be no reason to have an NT5E master socket as there was no internal house wiring to connect.

[#8]

and some of dont even have that, this is my master socket, and 8128 synch 7150 profile

[#9]

Quote from: Oldjim

Very simply - if, when the socket was installed, there were no other sockets in the property then there would be no reason to have an NT5E master socket as there was no internal house wiring to connect.

Sorry, Jim, but I don't buy that.  My case in point was a new house built, I imagine, around 1990.  There are several extensions wired from behind the walls so surely put in by the builder.  My friend has owned the house from new and had no recollection of installing them himself.  His next-door-neighbour has the same non-standard master socket but further down the street (and built a little later) I found a house with the standard NT5E master socket (bearing the Piper logo).

[#10]

Quote from: pierre_pierre

and some of dont even have that, this is my master socket, and 8128 synch 7150 profile

Socket isn't quite the right name, is it?  That looks like an old pre-privatisation junction box which you were not supposed to tamper with.  You might want to remove the photo before the phone police come knocking at your door!  The original rationale for getting a master socket fitted was that post BT privatisation you were allowed to install your own telephones and telephone extensions.  Before that BT had a monopoly.     

[#11]

Quote from: ReedRichards

My friend has owned the house from new and had no recollection of installing them himself.  His next-door-neighbour has the same non-standard master socket but further down the street (and built a little later) I found a house with the standard NT5E master socket (bearing the Piper logo).

Quote from: ReedRichards

Despite the fact the my friend's house is about 15 years old he has lived there since it was built, it does not have a BT Master Socket with a detachable faceplate.  The BT cable comes out of the ground in a standard BT sheath, through the house wall and into a dual phone socket with a BT 'T' symbol on it.

It's not rocket science, as I stated earlier BT did not, does not have a dual master with a removable faceplate

[#12]

No itsme, and this unusual master socket does not have a removable faceplate.  I don't see your point.