Hi all. Recently my phone has been making loud screeching noises like a fax machine during calls, together with electronic beeps etc as if someone is pressing their phone keypad. I've reset to factory settings twice to no avail. It's not all my the time, just once in a while, but the screech can be deafening. Is this a phone fault, a network fault maybe? I'm at a loss now. Many thank's. Mark.