On Saturday (05/30/2009 at 10:37AM +0100), Gordon JC Pearce wrote:
So, you can't see a possible set of circumstances where having the wrong
voltage coming in the serial port could cause the frequency shift to be
wrong?
How clever do you think the tone generator side is?
Well, as Tony replied-- I think that the RS232 input is a logic level.
It's not an analog level. So, you are going to get either the mark tone
or the space tone and not something in between.
I think this situation was just a poor explaination of what went wrong.
Whatever miscable situation he had caused him to generate the opposite
tone of what he was expecting but not a tone that was off frequency from
one of the two possibilities.
He was also off the mark (so to speak) by attempting to explain it as
on-off keying rather than the FSK that it really is.
Chris
--
Chris Elmquist