But do you get the speed In a message dated 7/26/2013 10:41:02 A.M. Eastern Daylight Time, [email protected] writes:
I have enclosed a sketch of the usual way of using opto's to make an RS232 like interface. I haven't spent much time thinking, so I am sure that I have a few things backwards, but you should get the gist of how it is done. It is only RS232 like because it has only a single threshold. -Chuck Harris Rex wrote: > FWIW, it was clear as mud for me too. > > Bert began with, "Since joining time nuts over four years ago I have not used a > single MAX > 232 chip. Two reasons MAX do not give me isolation and do generate noise > in critical applications." > > From that I took that he was doing RS232 using opto isolators. That implies + and - > voltages to me. Where do they come from and where are they relative to the isolation > boundary? If the goal is really isolation, how do these supplies get isolated? If the > noise is cured by isolation, these details seem important as the supplies need > isolation too. Maybe the switcher in the MAX232 is causing the noise. Then how do we > get a negative supply from, say, +5V without the noise? Then, maybe he was saying > RS232 sucks and this other way (not RS232 compatible) works better. > > The word picture of Bert's solution, which provided more details, left me less much > less than clear too. Maybe I'm just not up on circuit shorthand terminology enough to > follow what sort of current limiter is limiting what current to what, and what is > being blocked by a diode from which negative level. Not really sure if I even got the > big picture of what he is describing. Is it an isolated equivalent of a MAX232 > interface or something else that wouldn't talk to an RS232 device? > > So, more clarification, or possibly that picture (~= 1k words) might help. Or maybe > I'm just obtuse and everyone else is getting it. (Seems Marki may also be in the > confused camp.) _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
