Well, and the first really 50 years of telephony - you were probably as likely to have an uninsulated line as an insulated one. Remember that the first telepho

Well, and the first really 50 years of telephony - you were probably as likely to have an uninsulated line as an insulated one. Remember that the first telephones were 1-wire with a ground return, and that configuration was quite common until the early 40's.