() .
:
( )
( )
(ISO) , ISDN. .
, , (. 1)
OSI | ||
7. | ||
6. | ||
5. | ||
4. | ||
3. | ||
2. | ||
1. | , |
1. .
.
.
( ), .
. . . . i i+1. 1 .
:
7-5 .
4-1 .
ISDN
ISDN .
ISDN :
(C- Control)
(U User)
ISDN
, C, , ..
, U, .
.
()
|
|
ISDN :
BRI (BasicRateInterface) .
PRI (PrimaryRateInterface) .
BRI : 64 /. D 16 /.
BRI 144\.
. BRI -.
D . : , -, -, ISDN- .
BRI
2 BRI.BRI (TerminalEquipment) .
2. BRI
(1) , S.
(2) , (TerminalAdapter).
:
( )
NT2 2 (Networkterminationtype 2) , . NT2 S . , S T , , NT2 NT1 .
(Networkterminationtype 1) , . NT1:
NT1 S U.
LT - . LT NT1 .
, . .
S/T
1 ()BRI NT S/T.
3. S/T