BSNL Telephone — a very large grooming sound when phone comes while taking the internet

sir,
my phone has a grooming sound when me receives a phone call while the net connection is in use. so in order to reduce this the connection wires are to be changes or under ground cable connetion is to be installed. the connection wires are are connected in so many pieces, so please give a good connection.

THANKING U

YOUR FAIHFULLY

BRAJESH KUMAR SINGH