REIN, or R
oise to give it its full & fancy name is one of the biggest bug bears of broadband. In short this is interference on the telephone line that affects the broad band speed &/or stability. It can be caused by numerous things, from nearby transmitters to street lights & flashing Christmas lights!
The good news is there are a couple of devices that can be fitted to try & combat this. First off it the BT 80BRF3 :-
This small device is fitted upstream of the master socket, screw terminals connect to the incoming line & IDC terminals connect to the cable that feeds the master socket. The RF filter cuts out the radio interference which in turn improves broadband speed & stability.
The second device that can fix this problem is the BT VDSL faceplate :-
This is a filtered faceplate that is compatible with ADSL & VDSL, it features a filter similar to the 80B RF3 to combat REIN but also features full ADSL/VDSL filtering (so no need for ugly plug in filters!).
For the NTE5A socket the BT MK3 VDSL faceplate is considered the best filtered faceplate currently available (available until current stocks are exhausted-see below). Unlike the 80B RF3 solution no re-wiring is required, the faceplate simply slots onto the NTE5A master socket (also available, https://www.run-it-direct.co.uk/bt-line-boxes-and-sockets/nte5-nte5a-bt-openreach-socket/
For the new NTE5C (Mk2) type socket the MK4 or G.fast faceplate is the equivalent :-
In severe cases BT Openreach state BOTH devices can be fitted to a line, it should be noted however that this can result in reduced sync speed.