1068 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER 1953 



having done so, any red can be seen, more holes have been enlarged 

 and/or more tabs have been removed than the template calls for. If, on 

 the other hand, openings in the template are visible through holes in the 

 card that have not been enlarged, the hole coding is not complete. If 

 tab notches appear in the template other than in registration with the 

 portion of the card from which tabs have been removed, the tab coding 

 is not complete. Accordingly, the template also serves as a convenient 

 means for checking the coded card for accuracy. As a convenience, the 

 holes of the template were made round and its tabs triangular. 



The holes of the card before being enlarged are of a form and size 

 that simulates the filament face area of the light source. To accommodate 

 the 118 holes, the optimum dimensions of the holes were determined to 

 be %" wide, 0.140'' high and the optimum vertical and horizontal spac- 

 ing proved to be 0.535'' and 3^", respectively. 



The tabs are of a form and size determined largely by the mounting 

 space required for the solenoids that are used to operate the code select 

 and card support bars, the vertical displacement required for shuttering 

 the holes and ruggedness considerations. Thus, the nominal size of the 

 tabs associated with the code select bars became 3^" wide X 0.205" 

 long with a spacing of J^e''- The tabs associated with the card support 

 bars — one at either end — being used for each translation instead of 



COLLIMATING 

 LENSES ^ 



n a^-X 



PULL-UP 

 MAGNET 



UPPER CARD 

 " GUIDE BAR 



/ c=)i=!(=ic=3i=]l_Ji=]^i, D / c=ic=ii=ic=ii=ic=ir=] \ 

 / -^^^ / \ 



/c=Diizic=ic3c=ic=icniz=]cz3\^ ^[Z!t=iic3c::3Ci]cnCIICIIII^ 



?' 



c=ic=3i=DnncDnna \ 



CIldZlciDcrjcncDcncr] / 



pi CD D 1=1 1=3 n CD CqJI^ 



t=II=II=lI=)l=ICZ]l=ll=IC= 



i=ii=]cni=ii=]t=ii=ii=ic=i 



I=ll=lI=ll=lt=li=lt=ICZIC=l 



CARD 



SUPPORT 



BAR 



f/PATH OF FLUX\\; 



\-Q^ c=i t=] n t= (=1 u c 



, BAR DOWN STOP 

 UNOPERATED MAGNETIC 



CODE SELECT POLES 



BARS 



CARD BIN 

 7x BAR 



BAR UP 

 STOP 



^ I BAR DOWN STOP / ■ tHI I\ oc, nr-r,zr. T " ^, 



SELECTED 



CARD DOWN 



STOP 



CARD SUPPORT 

 LIFT MAGNET 



PULL-DOWN "LOWER CARD GUIDE 

 MAGNET BAR (FIXED) 



OPERATED CODE 

 SELECT BARS 



Fig. 20 — Card and directly associated components. 



