What would be a simple way to convert RS-232 +/-12 V digital levels into +5/0 V respectively?
- I considered an optocouple, but I can't find one that can withstand -12 V reverse voltage. I considered adding a two-resistor voltage divider, but I suspect that will worsen the slew rate of the device, and I have no idea if that will be enough to become a problem (I'm aiming at the switching speed of 19 200 baud).
- There's this simple answer, but it requires a transistor that can withstand +/-12 V as well - I'm looking for one right now but haven't found a suitable part yet. I'm also slightly worried about not having galvanic decoupling.
- I considered a 5 V linear stabilizer, but I suspect it may not be fast enough to turn off/on, after all, they weren't designed for this task.
Perhaps, an optocouple with a bulky diode in series capable of withstanding -12 V?