I should have worded that differently if I connect on of the phones into the one of 5 phone jacks it makes the line go dead in a sense. People will call and it will give them two rings and then cut out on them or it will just say the line is always busy. There are three lines connected to the box outside one goes to the shop one goes to one room in the house and the other is the main line into the house. I no longer connect all five phones and would be happy with just one or two on the line. The phone line only acts like this when only one of the old phones is connected to the line