This is an old revision of the document!

Building your own level converter

To adapt 3.3 TTL logic from NAS to +15/-15 PC serial, you can build your own converter. This schema is from Sodoityourself with two errors corrected and explicit pinout for DB-9 female.

Please note that MAX232 circuit cann't use 3.3 Vcc from serial Vcc, you must pick up 5V elsewhere (on board or from external power supply), or else use a MAX3223, that accepts 3.3V power supply. The original schema came with Rx and Tx swapped one with each other, have a look to RS-232 datasheet if any doubt.

This schema is easy to apply on a evaluation board.


Personal Tools