436 THE BELL SYSTEM TECHNICAL JOURNAL, APRIL 1951 



Fig. 13 — Aluiniiiiiiii alloy (lie (asiiii.u l-.i ilic low <;r()ui) 1 raiisiiiil t in;; subassembly. On 

 the front of the tasting may be seen tlie equipment designations. The large number of 

 holes in the rear surface provide clearance for filter terminals as well as filter mounting 

 holes. In the middle portion of the casting are a number of pockets used to hold miniature 

 transformers. 



