One quick question, when you mention the nte is in a passage, it this an area which other occupants have access to so there is a security issue ?
If thats the case then an nte5b is what you looking for, identical to the type a but the face plate has no socket to plug into. the wiring comes off the back of the face plate into an extention somewhere in order to get service.
Some times fitted in a shared accomodation situation or sometimes if the line is dedicated for an alarm and the company paying for the line dosn;t want any one in the comecial property inadvetently using their line for normal calls