Actually before that came paper insulated cable: http://www3.alcatel-lucent.com/bstj/vol12-1933/articles/bstj12-1-1.pdf http://www3.alcatel-lucent.com/bstj/vol1

Actually before that came paper insulated cable: http://www3.alcatel-lucent.com/bstj/vol12-1933/articles/bstj12-1-1.pdf http://www3.alcatel-lucent.com/bstj/vol12-1933/articles/bstj... These cables had paper pulp insulation around the wires, and a jacket of soft lead around the whole cable. The cable is pressurized with dry air at the central office to drive out water, though flooded lines can still be a problem sometimes. If you see any dirty-light-grey aerial cable (usually 2-5 cm diameter) in a city, that's probably pulp-insulated lead cable still in service.