, ( ), , 300 3400 . 3 , 4000 , 3100 . , .
, xDSL, , , . , . , 3100 .
, , .
xDSL . -, , 3. -, . -, 56 /. , -, , , .
ADSL , 1,1 , . : , POTS (Plain Old Telephone Service); ( ); ( ). , , . , , DMT (Discrete MultiTone). 1,1 256 4312,5 . 0 POTS. 1 5 , . 250 , , .
, , . 50/50, 80-90 % , . 32 , . , , .
|
|
ADSL-. , NID (Network Interface Device). ( ) , , POTS (0-4000 ) . , POTS, , ADSL-. , , , QAM-, . ADSL , . Ethernet .
, , . . , , 26 , , DSL, DSLAM (Digital Subscriber Line Access Multiplexer), ADSL- , . , .
ADSL. DSLAM ADSL . (, ISDN) .
.
() : FDM (Frequency Division Multiplexing ) TDM (Time Division Multiplexing ). , . () , .
3100 . 4000 , . , . , . .
FDM . 12 4000 , 60 108 . 12 .
|
|
.
. (WDM, Wavelength-Division Multiplexing). , . . . , , .
, - . , , , , . 25 000 (. . 2.6), , 1 / 2500 10 / ( / ).