6.4.            529

        (-
);

    .

     12,     -
   .

    (Logical Channel Number, LCN)  
 ,  - (  -
 )    (   -
).    ,   
,  256.

  (Type)   . ,   Call Request -
  ,  .     ,  
  (  1)    (  0). 
  1   ,    ,  
      .     
 Type      N(S)  N(R).

         (DA 
SA)  .        .
      Call Request,     -
        -
   -.      ,
     Call Accepted   ,   
  ,  , , .    -
       .121  ISO 7498.

         
   .

    (Facilities length)   (Facilities)   -
  ,    . , 
      -
 (    ),     
   .      -
       
     ,    -
   . .  .25    
  : 16, 32, 64,128, 256,512  1024 .  -
  128 .

 Call Request      
  ,     .
         -
   LCN (  VCI,     -
  ).     .25 
.

         .25 -
   .  ,   
 ,        , -
  . ,     , -
    250 720,     1,  