Filter (also known as a Splitter) is a small device used to split
voice (telephone) and data (internet) signals.
Micro Filter plugs into the telephone wall socket and has a socket
for the telephone plug to go into and also a smaller one to fit
an RJ-11 plug that goes to the modem/router.
is important to add a Micro Filter to all the telephone sockets
that share the same line as the broadband that also have a telephone
attached to them. If you use the telephone for an incoming call
or if you are making a call through a socket that doesn't have a
micro filter then the Internet connection can be interrupted.
you have a socket that does not get used and has no telephone plugged
into it then should not need a micro filter added to them.
to note that when you order broadband you will most likely receive
1 or possibly 2 micro filters from your broadband
provider. If however you need more then they are relatively
cheap and only cost £6-£10.