
- on Microcontrollers
- Published in issue 7/2011 on page 24
RS-232 Level Shifter with Isolation

This circuit converts between the TTL voltage levels on a UART to the correct levels for an RS-232 interface, with the two sides of the circuit being galvanically isolated from one another. Although ICs are available to do this from manufacturers such as Maxim, they are rather pricey.
Correction
issued: June 27, 2011.
The schematic printed in the July & August 2011 edition is incorrect in a number of respects and should be disregarded. A corrected schematic has been released and is included in the article you can download as a .pdf file free of charge from this page.