1230 



THE BELL SYSTEM TECHNICAL JOURNAL, OCTOBER 1951 



Table XIX and (b) in annual totals during the period 1920-1949, plotted 

 in Fig. 35. 



Annual Prodtiction Totals » 



In general, the average and peak figures of annual production prior to 

 1920 were very small relative to those in the 1920-1949 period covered by 

 the chart. For example, the maximum annual production of side circuit 

 and phantom toll cable coils prior to 1925 was in the war year 1918,* and 

 the maximum annual production of non-phantom exchange area cable coils 



Table XIX 



Accumulated Total Production^^^— Voice Frequency Cable Loading 



Coils (in Millions of Coils) 



Notes: (1) All production figures are approximate values. 



(2) Commercial production of side and phantom coils did not start until 1910. 

 Up to that time non-phantom coils were used for toll cable loading (and for 

 exchange area cables). 



prior to 1923 was in the war year 1917. f Thus, with occasional exceptions, 

 the production data for the years prior to 1920 could not be accurately 

 plotted on the chart without using a confusing s:ale. 



In the beginning, the use of loading was small relative to its subsequent 

 use because the Bell System cable plant was small. For nearly a decade the 

 expanding toll cable plant used fewer coils than the exchange plant. From 

 then on, in the two-decade period 1913-1932, toll cable loading dominated 



♦ 117,000 coil peak in 1918; 187,000 coil total in 1925. 

 1 33,000 coil peak in 1917; 38,000 coil total in 1923. 



