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THE BELL SYSTEM TECHNICAL JOURNAL, JULY 1952 



nel unit, shown on Fig. 34. The same basic die-casting is employed, \vith 

 minor rearrangement of the die, for the two t\vin channel units, the 

 group transmitting unit, and the group oscillator. The part of the slide 

 arrangement associated with a plug-in unit is shown at the top of the 

 twin channel unit. 



All plug-in units are held in by a common cover (Fig. 24) which en- 

 closes the handles of the units. For additional support a rapid action 

 fasterner holds the tops of the channel and receiving group units. 



Repeaters may be either pole mounted or placed in a central office. 

 A group of two repeaters is shown on Fig. 35. This assembly employs a 

 framework, shown on Fig. 36, which includes the same slide die-casting 

 as the terminal. A central unit (also plug-in) accommodates the two 



Fig. 31 — Group receiving or repeater unit. 



