506     6   _________________________________

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 ,     V.90      
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^^ 33,6 /.    
V.90        ,    -
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6.3.2.     Switched 56

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    64 /      -
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        Switched 56, 
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.  8-      ,
         
 56 /.     Switched 56 
 . 6.15.

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 1/1.        
    2400 /  56 /.   Switched 56
      ,   