There is quite a lengthy history behind this.  To summarise in a crude
fashion, telephone lines can only really handle about 9600 max.  By using
some clever compression and error handling techniques, they increased the
speed to 14.4k, 28.8k and then 33.6k.  Then, hitting a barrier with that
technology, by rethinking the problem and using DSP to handle some really
clever compression, they upped the speed again to 56k, which started with
56k flex, and then the very clever V.90.  Then, by rethinking the problem
completely again, introduced FFT and cleverer DSP's, and came up with ADSL.
I think this explains why thinks get different after 9600 baud.  The guys
who invented these techniques were indeed very clever.

Rgs
Ian.

> -----Original Message-----
> From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of James Newton, Host
> Sent: Wednesday, 21 January 2004 11:18 am
> To: PICLIST@MITVMA.MIT.EDU
> Subject: [EE] Why don't baud rates just double?
>
>
> Why is each higher baud rate twice as fast until 14.4K which
> is only 1.5
> times faster than 9600?
>
> 115,200
>  57,600
>  28,800
>  14,400
>     ?
>   9,600
>   4,800
>   2,400
>   1,200
>     600
>     300
>
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