This front-plate was easy to fit and produced a significant increase in the down-stream noise margin of my line from 17db to 22db with much greater stability. It also decreased the line attenuation from 29db to 27db more or less immediately.
It will take some time before the situation stabilises to see if the result will be greater download speeds and less router reboots, although initial results are very promising. I used to enjoy a stable ADSL service for months on-end but then BT "upgraded" my exchange and the link became eratic. Before the new face-plate was fitted, my ADSL link was going down briefly more or less every day. That has now stopped. The link is stable again and hopefully BT's exchange equipment will increase my downlink speed in-line with the increased stability. I have downloaded a screen capture from the excellent Routerstats programme which shows the noise margin before and after the faceplate was fitted. The increase in noise margin is self-evident, as is the increased stability. In fact, my downstream connection rate increased from 4,500 to 6,600 kbs within three days, and, after ten days of stability, the BT exchange equipment raised this to 9,724 kbs, the highest I have ever received. Postscript: by the end of June my downstream rate has increased to 14,000 downstream, 1,176 upstream at 6db noise margin; it remains to be seen whether the link will hold at this rate.
Besides a much improved performance over the BT "i-plate" that it replaced, there is no longer a requirement for messy individual filters on each of my extensions.
The Solwise web site gives an excellent account of how and why these things work and the instructions supplied with the faceplate are more than adequate.
As one of the other reviewers suggests, you need to be able to place the ISDN router next to the master-socket and face-plate in order to get the lowest possible noise ratings. The face-plate provides for an un-filtered extension line to be installed if a remote router location is unavoidable, but this does risk increasing the line-noise. The optimum solution is to have the router as close to the master-socket as possible with Cat 5 cabling from the router back to computers and remote access points.
No special fitting expertise is required so long as you follow the supplied instructions carefully. In my case it took just ten minutes from start to finish. An insulation displacement tool is useful for fitting any extension cable wiring, but not essential if you are careful and use something like a jeweller's screwdriver to push the cable into the terminal.