LEAD-COVERED PAPER-INSULATED TELEPHONE CABLE 437 



by step it is thus built up, one layer being applied by each drum until 

 the full amount is obtained, after which an outer wrapping of paper is 

 applied to retain the insulated wires in shape and also serve as an 

 additional insulation from the lead sheath. 



All telephone cable for local service (exchange cable) until recently 

 was made in much the same manner. Recently two new processes 

 have completely revolutionized its manufacture. 



,. ^^ 



Fig. 4 — -Typical construction of long distance telephone cable. 



Direct Application of Wood-Pulp Insulation 



The process and machine recently developed to apply wood pulp 

 direct on wire combines the steps of paper making, slitting, (Fig. 5) and 

 insulating (Fig. 6) into one operation, and gives a continuous sleeve of 

 pulp paper around the wire. 



Essentially, the process consists in forming simultaneously on a 



