Cape Town-Johannesburg carrier telephone and associated voice-frequency telegraph system
14 July 1936
This system affords the following facilities: fifteen V.F. full-duplex telegraph circuits and two carrier-telephone channels in addition to the usual audio-telephone outlets. The telegraph channels can be increased to eighteen when the need arises. The telephone circuits are brought out on the long-distance boards at Cape Town and Johannesburg and used for S. African and overseas traffic. Creed Page printers are used almost exclusively for telegraph traffic although Creed-morse is worked on one or two channels. In addition to the usual direct facilities two outlets are available for leased part-time service (teleprinter private wire) between Johannesburg and Cape Town Telex subscribers. Overseas telegraph traffic is also routed over the equipment. The installation was commenced in April, 1934, and the circuits were opened to traffic on November 1st of that year. The route is 922 miles in length. With the exception of short carrier-loaded entrance cables at the terminals, the route is of copper 150 lbs. per mile throughout. The route is partly "revolved," the remainder having point transposition. The entrance cables are approximately 1000 yards in length of multi-twin conductors of 40 lbs., and loaded with intermediate 3.5 m.h. coils at 250 yards intervals. The equipment is fully described with diagrams.