Blocks upto 100 per cent of nuisance calls fed up with sales calls interrupting you at home bt brings you the bt4600 a cordless big button phone with integrated answer machine and call control functionality that blocks nuisance or unwanted calls powered by truecall call blocking technology the bt4600 puts you back in control by enabling you to choose the calls you want to take and those you want to block you can also free up your hands using the handsfree speaker and easily copy contacts