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Why in dial-up the limit is 56Kbps and the DSL can have more

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safwatonline

safwatonline

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DSL

hello,
i was wondering why in Dial-up we can max. have a 56Kbps and the DSL can have more BW, i know that the Dialup 56kbps came from the 64kbps PCM (using one bit for check or parity) but if the channel can hold more rate as the case of the DSL then why the modems "dialup" are limited to the 56k.
also in DSL do we have a max. speed limit "especially from the channel BW limitations"
thnx. in advance.
first one gets three points :D
 

Re: DSL

hi

its understood that DSL can handle more data

its bcz 56k modems r designed for tcp/ip connections and have relatively very low speed for data transfer. the data speed that we see is the max speed which is not offered so 56k has actual speed round about 7kBps.

but DSL can handle more data as its own speed limits r great

also its possible to give high speed on 56k(about 15kBps) modem but then what will ISPs get. it means its also for the gain of money from users
 

    safwatonline

    safwatonline

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DSL

sorry but i dont get u , so here is my question again"may be i am not clear",
in DSL we use the same channel as the Dialup , So y the DSL is unlimited while the Dialup is limited .
i know the rates and i know the types of modulation , but i didnt get what u meant by the 15kBps , if that is possible why we never heard about a Modem of that speed.
BTW i want to know the difference between the DSL and ISDN also?
thnx alot.
 

Re: DSL

hi

ok
i think i m not clear

actually i want to tell that
a given connection has a given range of speed. ye we know that same lines r used for each communcation but connection hardware which we use has a differencein some matters like

working time
working capacity
connection handling
port setting
simultaneous connections to isp

isdn is not much different then dsl is has actually differnce in hardware so port setting in operating system is given as isdn

now when comes simultaneous connections.dslcan handle more than 100 connections to web.but 56k modem is recommended to use only 4 connection simultaneously.
 

Re: DSL

safwatonline said:
hello,
i was wondering why in Dial-up we can max. have a 56Kbps and the DSL can have more BW, i know that the Dialup 56kbps came from the 64kbps PCM (using one bit for check or parity) but if the channel can hold more rate as the case of the DSL then why the modems "dialup" are limited to the 56k.
also in DSL do we have a max. speed limit "especially from the channel BW limitations"
thnx. in advance.
first one gets three points :D
Click to expand...

ADSL B.W is 1MHz and theoritcal rate at short loops is 8Mbps
ADSL2 B.W is 1MHz and theoritical rate at short loops is 12Mbps
ADSL2+ B.W is 2.2MHz and theoritical rate at short loops is 25Mbps

While in the case of dial up modems the B.W is 4KHz (the bandwidth of voice channel)
 

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