Whilst renovating my study I looked into the possibility of moving my BT socket outlet and so tried to identify the 'Master Socket'. To my surprise I found that the apparant Master (which is a very dated BT LJ2/1A) connects back to a wall outlet marked 'GPO' , which was hidden behind an old cupboard). That outlet has a crude screw block connection behind the face plate (no gels or insulation) where it connects to the incoming BT wire-sheathed cable.
Does anyone know whether the 'Master Socket' would be regarded as the LJ2/1A or is it the old 'GPO' socket ?
Given the date and standard of the installation up to the LJ2/1A, should BT upgrade this to NTE5 or filtered face plate ?
is there a problem with your phone line? if not openreach won't fix/change the socket for free. however if you have line noise on your phone and need an engineer to fix then he should upgrade the socket
as I said if you have line noise then report it to 151
try quiet line test dial 17070 option 2 should be silent no hiss/crackle and best with a corded phone if cordless then dull hum normal
The master socket is always the socket, not just a junction box. The only exception is some new build installs from a few years ago when BT thought it would be a good idea to make the "master socket" a grey box on the outside of the house.
A junction box wouldn't normally be a problem if the connections are good. Beware - if the terminals are corroded, then Openreach may charge you for not looking after it if an engineer call-out is needed.