- , .. . - N N*(N-l)/2 . .
:
- , ( FDM), ( TDM). ;
- , . , Switched 56 ISDN (Intergrated Services Digital Network).
(Plain Old Telephone Service POTS - ; Public Switched Telephone Network PSTN - ). dial-up access.
- 9600 /, 56 /. , .
. . , .
ISDN .
- .
Switched 56 , 4- T1. Switched 56 . 8.8.
. 8.8 - Switched 56
, DSU/CSU . 8- 56 /. , .
, . - 2400 / 56 /.
Switched 56 , 56 / , .