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I understand that RS232 Communication voltage levels should be between 3 and 25 Volts for positive voltages and the equal negative for negative voltages, but is there a source that can explain the real-life wave forms? It is pretty obvious seeing a 'perfect' signal, but in real life, I deal with signals that have oscillating and varying voltage levels. and I do not know what would count as a noisy refutable signal and what doesn't.

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The Wikipedia article has an image that's fairly representative of what you should see in real life:

enter image description here

The rise and fall times are non-zero, the high and low levels are not necessarily all that stable or smooth (especially with charge-pump drivers) and there's a bit of overshoot/undershoot.

But if you look at the part of the waveforms between +3 and -3V (and a fair ways beyond that) they're very clean. +/-3V are the detection levels of the receiver, so it doesn't care what happens beyond those levels, +15 is the same as +3. The additional voltage gives you noise immunity.

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You have met the big advantage of digital data communication: The original signal can be guessed perfectly if the errors during the transmission are small enough.

Continuous voltage signals aka analog signals cannot be fixed back to perfect shape if the transmission distorts them and adds noise in a random way. Imagine you receive noisy, rounded and possibly also ringing pulses. You have a possibility to know what they exactly were only if you either know exactly what imperfections the transmission inserted or you have a limited collection of signals that the original must be.

Digital data just contains only a limited collection of possibilities to select from.

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