S-6 carrier system on unloaded cable

Using the first carrier band group, 32-56 kc/s, of the S-18 system, with unloaded 1.2 mm conductors and repeater stations at every 50 km, the S-6 system imposes 6 channels on each conductor in a toll line of ~600 km. The circuit completely satisfies the specification requirement of a s./n. ratio of 50 db and a signal/distortion ratio of 55 db, while the signal/crosstalk ratio of 60 db is achieved provided no cable crosstalk exists. The terminal equipment, common carrier supply equipment and the repeater are so designed that they can easily be applied to an S-18 system whenever such a change-over becomes necessary. The S-6 system is recognized as being preferable to the S-18 system for circuits of lower traffic demand and economically advantageous while a shortage of equipment exists.