358 



THE BELL SYSTEM TECHNICAL JOURNAL, MARCH 1953 



The essential features of the throwdown runs to date are given in 

 Table III. 



The curves of Figs. 27 and 28 are representative of the type of data 

 made available by the throwdown machine. Fig. 27 shows the overall 

 dial tone service obtained during the first two runs. The shght degrada- 

 tion of service in Run II is caused by the reduction in number of registers. 

 In both cases, however, service is very good. 



Fig. 28 shows the spread of delays met by line fink frames in obtaining 

 a marker on dial tone calls during the same two runs. These curves are 

 representative of the distributions of delays encountered at individual 

 stages of handling a call. Other examples might be line link and trunk 



1.0 

 0.8 



0.6 



0.4 

 0.3 



0.2' 



O.I 

 0.08 



m 



^ 0.04 



0.03 



0.02 



0.01 

 0.008 

 0.006 



0.004 

 0.003 



0.002 



0.001 



0.8 



1.6 2.0 



2.4 2.8x 

 '0 



TIME, T, IN SECONDS 



Fig. 28 — Marker delays on dial tone calls with different equipment quantities 

 determined by the throwdown machine. 



