LEAD-COVERED PAPER-INSULATED TELEPHONE CABLE 443 



changing take-up spools are necessary. Individual wires are strung in 

 without shutting down. Tension devices are incorporated in the 

 take-up so as to avoid the possibility of any undue tension being put 

 on the finished wire. The normal speed of the machine is approxi- 

 mately 110 ft. per min., and the output per week is about 45 million 

 conductor feet. 



The electrical properties of telephone exchange cables made from 

 this material compare favorably with those made from ribbon insula- 

 tion, and the annual saving per machine is an appreciable factor due 

 largely to the lower cost of raw material. 



Improved Cable Stranding 



Until recently all local cable (exchange cable) was built up or 

 stranded by the concentric layer method at a speed of 50 to 100 ft. per 

 min. (Fig. 8). This construction is being rapidly superseded by a unit 



Fig. 12— 1818-pair unit cable. 



