delabs Circuits

Monday, November 10, 2014

Isolated Full-duplex Serial Interface

I would like to build Optoisolated RS232 interface. I've googled a little bit, and I came across your design:

RS232 with Opto-Isolation

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

Isolated Full-duplex Rs232 Interface

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 also Isloated Interface to Microcontroller

See a Commercial Solution you can buy

CVT-232A-3 port-powered 3-wire RS232 Isolator

CVT-232A-3 port-powered 3-wire RS232 Isolator

"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."