why do we use 56k modems

[nigelnibbles]

can anyone answer this, why do we use a 56k modem on a normal phone line, can you get/use a bigger one, and would you be able to download things quicker(assuming we cant all afford broadband)just something i wondered about :confused:

[Newt]

50K is about the best you can get with a dial-up line and that only if you are fairly close to the main phone company switching equipment. Not sure about the UK but in the US if you are 3 or more sub-stations away from the central office, you won't see much faster than around 35K.

 

The reasons are technical and way over my head but as I understand it, using the best error correcting and some compression, 50K is some sort of a limit. There are some newer compression routines available that will give you more data so it will appear faster but if you could buy a 112K modem, you'd still only get the 50K or 35K or whatever thru put.

 

One issue is the fact that a dial-up modem has to do lots of translation. It takes a digital data stream from a PC, translates it to analog and onto the phone line, then back to digital at the other end so a PC can deal with it.

[corydoras]

It is all to do with the maximum baud rate of the standard phone system (POTS, Plain Old Telephone System)

 

This pdf file explains it more succinctly than I ever could.

 

I hope that your maths is up to it.