I would like to build Optoisolated RS232 interface. I’ve googled a little bit, and I came across your design:
However presented schematic is of poor quality – I’m not able to read all parts numbers and their values. Is it possible for you to send me a copy of this schematic, which is more readible?
Mail from M from Poland
You had written to me a few months back, I suggest this circuit
This self powered interface circuit electrically isolates the TxD and RxD lines from the PC serial port and protect the PC from direct connection to hazardous voltages.
See a Commercial Solution you can buy
“The unit features 5000V opto-isolation circuitry and optically isolates three (3) RS-232 lines (TX, RX and GND), which effectively protects your RS-232 devices from ground loops, noise problems, transient surges, remote lightning and spikes.”