Carrier in cable

IN ORDER to meet future demands for high-grade and economical circuits in cables, considerable carrier development work has been done which has included an extensive experimental installation on a 25-mile loop of underground cable. Sufficient pairs were provided in the cable and repeaters were installed to set up 9 carrier telephone circuits 850 miles long. Tests on these circuits showed the quality of transmission to be satisfactory, while the methods and devices adopted to prevent interference between them were found to be adequate. The trial has, therefore, demonstrated that the obtaining of large numbers of carrier telephone circuits from cable is a practicable proposition.