This page is archived and is no longer receiving updates.
It remains here because some of the content may still be useful.
Level Converter
Most of our gadgets have serial ports that work at 1V8 or 3V3 single-ended; our serial concentrator expects true RS422 or RS232, at ±12 to ±25V. So we need to provide a level converter/driver to convert between the low level single-ended signals on the boards, and the high-level differential voltages for transmission to the serial concentrator.
We used the suggested circuit in the Manufacturer’s Datasheet, laid out on a piece of perfboard.
This picture shows one wired to convert a single channel; because most of our gadgets need only a three-wire interface, you can convert two channels with one chip. The converter is powered from the gadget: provide 1V8 or 3V3 depending on the signalling level.