There is a little history impairment going on here methinks.

The "standard" baud rates:
 38,400
 19,200
   9,600
   4,800
   2,400
   1,200
     600
     300

were intended for baseband communication and are harmonically related as you
observed.  In the early days, modems also matched these "standard" baud
rates.

However, modem makers found that by using different encoding techniques,
they could get speeds greater than 9,600, but not always quite up to the
next standard frequency.  So we had 14.4, 28.8, 33.6, 48.4 and 57.6 (and
probably a few others).  These were derived from the technology, rather than
from any sort of standard.

I believe 115.2 was simply a way of getting data into the PC faster than the
modem could move it across the landline ... I don't believe it is/was ever
used much for out of the box communications.

72/73 de WB8RCR    http://www.qsl.net/wb8rcr
didileydadidah     QRP-L #1446 Code Warriors #35


----- Original Message -----
From: "James Newton, Host" <jamesnewton@PICLIST.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Tuesday, January 20, 2004 7:17 PM
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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