If youre plagued by calls from salesmen and overseas call centres this little gadget will help incredibly easy to use the call blocker mk ii is compatible with all domestic phone lines even those with broadband unplug the cable from your telephone and connect to the call blocker then connect back to your phone using the mini cable provided the call blocker is pre programmed to block around 200 rogue callers already known to the call prevention registry and you can add another 1000 numbe