Sometimes you need to connect something with serial RS232 bus, a good way is this:
« The MAX232 is an integrated circuit, first created by Maxim Integrated Products, that converts signals from an RS-232 serial port to signals suitable for use in TTL compatible digital logic circuits. The MAX232 is a dual driver/receiver and typically converts the RX, TX, CTS and RTS signals. »
Update 1: Here is a simple Rs232 interface, basically it was designed for a another avorted project, click on the picture to got the layout (Ares) file.
I’m plan to build a new improved GPS Logger, i design the pcb right now, and make some test with Arduino Mini and EM-406, the change are, a new charge pump , charging unit, and GPS PA6B module
Prototyp test
The SDCard socket from Molex
The trace result example from my last trip in Canada with the first version