National Geographic : 1929 Mar
Getting there ahead of the trouble An Advertisement of the American Telephone and Telegraph Company DURING the afternoon of March 17, l 1928, an alarm bell rang in a tele- \ phone test station in the heart of the Alleghany mountains. This meant that a puncture had been made in the air tight sheath of a busy inter-city cable. The men on duty knew that the injury was somewhere within 50 miles. Highly developed locating devices were instantly applied and in sixty-five minutes the trouble spot was located. By 7.15 in the evening, before the break in the sheath had affected service on any of the 248 pairs of wires in the cable, the repairs had been made. Because of the preliminary warning on the indicator wire and the locating devices that enabled the test station to tell the repair crew where it would find the trouble, not one conversation was interrupted. This special alarm system is one of the S many mechanical and electrical won °c ders developed by Bell System engi neers to guard telephone conversa tions. The apparatus is placed along the cable routes at intervals of 100 miles. It gives instant warning day or night of any disturbance to the cable within 50 miles in either direction. Automatic warning signals, electrical locat ing devices, constant testing of all switch board apparatus and circuits-these are some of the ceaseless efforts that so effectively reduced interruptions to service on Bell lines in 1928. There is no standing still in the Bell Sys tem. Constant progress in accuracy and better and better service at the lowest cost is its goal. "THE TELEPHONE BOOKS ARE THE DIRECTORY OF THE NATION"