582       

   VCI     , -
     .     -
      ?

18.    V.90        ,
    V.90.  ,      -
        .   
     ?

19.        :  ISDN 
 B+D,    64 /,  -
  frame relay  CIR64 /?

20.       ,   -
     frame relay.   NetBEUI
     ,      
,      ,  -
   .       ?