This adaptor faceplate replaces the lower faceplate on the BT main socket (NTE5) which then filters all sockets in your house.
There is no need for any other filters in any other sockets. This faceplate filter has the latest bell wire filter, the same as the 'I' plate, therefore the 'I' plate is not required.
This upgrade also enhances the performance of ADSL. The socket has two outlets, one for the phone and one for the modem / router. The connections inside allow all extension to be wired as normal from terminals 2/3/5 and two terminals (A and B) to allow the provision of a cable for an ADSL socket into another room.
Full instructions are included.