Searched around some and didn't find much of anything, can't believe this isn't already a known error. Anyone else aware of this?
Setting the serial monitor to 28800 or 14400 baud appears to actually set it to 9600. So a sketch like below produces garbage on the monitor when it's set to 28800. Same sketch with a different terminal program works as expected.
Now the funny part, I discover this while playing around with programming the USART myself. Did I calculate the UBRR value incorrectly? Control registers set incorrectly? Oh! Hmmm...
Actually I was lucky and figured out what was going on fairly quickly. That makes once 
void setup(void)
{
Serial.begin(28800);
}
void loop(void)
{
Serial.println("Hello, world!");
delay(100);
}
Which version of the IDE?
LMAO, 1.5.6 has resolved the problem, 28800 and 14400 are absent from the dropdown in the serial monitor.
That's just rude! (And lazy?)
Do you need those baud rates to work?
Nah, not at all, I can use another terminal program. I was just curious if anyone else had run into it.
Hmm, it works for me... (1.0.5)
Linux?
Windows XP. ...then I have to check what is the difference. I have 1.0.5, not 1.0.5r2.
Exactly. Try changing the baud rate in the sketch to 9600, and leave the monitor at 28800 (or 14400) and the output will be readable.
Yes, that's true! I completly forgot, during the time, that I replaced rxtxSerial.dll with downloaded one from this:
http://servicios.ried.cl/arduino/temp/rxtxSerial-2.2_fixed_2009-03-17.rar .
Originally the problem discussed here was about very long IDE startup time and lazy response on on tool menu (is not the problem of 1.0.5). [Guide] Fix Arduino IDE slowdown in Windows & replace the ugly Win7 taskbar icon - Installation & Troubleshooting - Arduino Forum.
To apply this and it solve 14400 and 28800 speed also.
Setting the serial monitor to 28800 or 14400 baud appears to actually set it to 9600.
Exactly! After some search I found that the version of rxtxSerial.dll included in Arduino SW does not support 14400 and 28800 baudrates and change it to 9600.
