I'm just wondering if there is any difference between the two because the ADSL filter has less of a Line attenuation than the faceplate. Are they both the same or is one better than the other?!
Perhaps the faceplate is not making as good a connection as the ADSL filter?
Also, its not known what extra components are in the faceplate, as basic ADSL filters are usually simpler.
Remember, all it is doing is preventing the broadband signal getting into your phone.
Its actual connection (sync) speed that you need to be looking at, not attenuation.