Arduino Severino help

Hi im going to make a Arduino Severino but i want to know how i can make a DE-9 to usb adapter i have a male DE-9 plug and a usb cable and i want to know where the 5 usb cables (black,red,green,white,and the one around all of them) go on the DE-9 pins or can i use a usb port and how instead of a DE-9 port on the arduino? thanks for you help

You want to end up with something like this? There is an IC or two that needs to go between them to translate the USB levels into the RS232 +/-10V levels. So you really need the equivalent of two things to make your own:

A USB/Serial adapter,

and a TTL to RS232 adapter, or

would one of these work?

USB To RS232 TTL PL2303HX Auto Converter Module Converter Adapter 5V 3.3V Output:

RS232 To TTL Converter Module Built-in MAX232CPE Transfer Chip:

unfortunately those wont work because the severino uses idle low serial like the old teletypes and pcs. so the device in crossroads first link is needed. i think you can ignore those next two links because they do the same thing but much more expensive. imo the severino is way too complicated and makes much more sense to just put the arduino chip and crystal on a board by themselves with a few header pins. this would allow use of a simple idle high usb/serial adapter wich would cost a fraction as much as the other options.