A house I'm buying has no normal master socket. It has a weird grey faceplate in the porch that says "PostOffice Telecommunications". From that two tiny little phone sockets have been wired off into different rooms:
I've never seen one of these before.
That is a perfectly normal BT66 and, as such, is no problem.
Your description of the sockets within the property suggests that there might be cause for concern. However without sight of how everything is connected together the situation is currently an unknown.
The worst case scenario is that you would require an Openreach technician's visit "to normalise the wiring and to fit an NTE5/C with SSFP".
The key phrase is within the quotation marks, above.
100% Linux and, previously, Unix.
Edited by burakkucat (Sun 18-Jun-17 14:10:49)