6.3.              507

 56 /     ,    -
  .

56 /

56 /

2 /
TDM-

. 6.15.   Switched 56

  Switched 56       .
      ISDN,   
,        
  .

RS-232C,X.21,V.35

	  
		| - |	  
		S?0 Q						>				) U	fsl		-
							'\ /'								
																
EH	4- 	1				)(						1	^	^	
						' \					
^		S		"					<						 ^		fl
																
				2 /	2 /	U	

6.3.3. ISDN     

     ISDN

ISDN (Integrated Services Digital Network      -
)   ,       
 ,      .  
        -
,         
,  .  ,     -
    .     IDN 
Integrated Digital Network.      -
         -
.        1959 .   , 
         -
  ,         
  .  ,     
       , -
 (    ),  ( -
      ),     .
         70- .
        1  

