1130 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER 1956 



uct or accuracy of a computation. In one form or another, testing is essen- 

 tial in manufacture. It insures against further investment of effort in 

 product found bad. More importantly, it provides information for the 

 manual or automatic correction of earlier processes, to prevent manufac- 

 ture of additional faulty product. Also, its techniques and devices are 

 used in many applications where testing is not the object. Table I gives a 

 listing of functions, with examples of some of our automatic means, that 

 illustrates this. Of these, la, 4, and 5a are testing functions. The remain- 

 der are manufacturing processes. 



Table I 



Function Example 



1. Sorting, either 



a. sorting good from bad or A network testing machine at Indian- 



polis.' 

 A relay coil test set at Kearny. ^ 



b. sorting into cells for selective as- A capacitor test machine at Haw- 

 sembly thorne.^ 



2. Adjusting: An adjusting machine for flat type 



resistors at Haverhill.* 



3. Calibrating: " A calibrating machine for oscillator 



film scales at Kearny.^ 



4. Plotting data: Continuous thickness test systems for 



alpeth and stalpeth cable sheath at 

 Hawthorne and Kearny."- ^ 



5. Operation of wired equipment, Cardomatic and tape-o-matic test sets 



a. to verify accuracy of wiring or ful- for key telephone equipments and 

 fillment of purpose, and wired relay units at Hawthorne and 



b. to enable prompt location and Kearny.^- ' 

 correction of faults. 



GENERAL 



The fundamental steps necessary to any testing operation are: 



1 . Putting the item to be tested in location ; 



2. Subjecting the item to a specified set of conditions; 



3. Observing the results or the reaction of the item to the conditions; 



4. Comparing the observed results to required results; 



5. Deciding on the basis of the comparison what disposition to make 

 of the item; 



6. Indicating the disposition; 



7. Making the disposition. (This may mean transportation, repair or 

 adjustment.) 



In purely manual testing all of these steps would be initiated by human 



