You know, this entire discussion requires a user to reliably hit the RETURN key. At least
once, at the right time, and after connecting with a modem, or whatever.
I have never had any confidence in a human _ever_following instructions. I worked for a
few years with a woman who always used the line feed key instead of CR (or return, or
enter, call it what you will, decimal 13).
I found that cycling through a limited list of baudrates based on framing errors, waiting
for the BREAK signal, was more reliable.