====== Note ======

These directions will only be helpful if your PC has an old-school serial port, and even then it's a lot of work. It's far easier to purchase a [[http://www.ftdichip.com/Products/Cables/USBTTLSerial.htm|USB to +3.3V level shifter]] to get the job done.

====== 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 [[http://sodoityourself.com/max232-serial-level-converter|Sodoityourself]] with two errors corrected and explicit pinout for DB-9 female.

{{howto:max_232_level_converter2.png|}}

Please note that MAX232 circuit can'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 your level converter's datasheet if any doubt.

This schema is easy to apply on a evaluation board.

{{howto:quick_and_dirty_serial_lvl_adapter.jpg|}}