I can hear a faint buzzing sound when I am talking on the phone.

I can hear a faint buzzing sound when I am talking on the phone.

Some cordless phone base stations are not properly shielded and can sometimes cause interference if they are near any electrical equipment. Try moving your Call Blocker unit
a few inches away from your phone's base station to reduce the interference. Also, 
make sure you have top quality ADSL broadband filters on the socket. If you do, 
it could require changing.