How does a microfilter work?
A microfilter works by taking the combined telephone/ADSL signal and splitting it into two different signals. The telephone plug on your microfilter is designed to limit the frequencies your phone is able to use. Although you would never normally use the frequencies outside this range, actions such as picking up the receiver can generate frequencies outside normal voice range. Without the filter, you will hear “noise”, and voice interference would corrupt data within the ADSL frequency band. The second socket is the ADSL socket, this is essentially the raw signal, i.e. unfiltered, so an ADSL modem will see the high frequencies, but can just discard the normal voice frequencies.
