____________________________________2.1.        125

 ,     ,     
 (    ).  
          -
 .

       . -
        . -
    :   .  
    -, -  .  -
      150    -
,     ;    150   20  
, , ;    20   1   -
  ,  .  
-    ,   -
 .     .

     .    
    AWG (American Wire Gauge),
     ,  22 AWG,
24 AWG, 26 AWG.     ,    .
       -
,     .    -
      .
,      ,  
        -
    ,  
,    . .   ,
, ,  ,      , -
 ,       .
,        -
  ,   NEXT      
  .

        
   - .

     

   UTP      -
    5  (Category 1  Category 5).
  1  2     EIA/TIA-568,   
568   ,  .

  1  ,      -
.           -
 ( 20 /)  .  1983     
   .

  2     IBM  
  .       
      1 .

  3    1991 ,   
      