Connect Uno and serial port on my computer.


I'am a new user of Arduino Uno and i am french...two difficulties :wink:
I am trying to use SoftwareSerial. I have connected Tx and Rx of my computer to digital I/O 10 and 11 of my Uno. Only that.
My Uno is on usb port (/dev/ttyACM0) and my I/O serial on my computer is /dev/ttyS0.
Here is the code :

#include <SoftwareSerial.h> 
SoftwareSerial PortSeriePortable(10,11);
void setup(){
        Serial.println("Salut le PC de bureau !");
        PortSeriePortable.println("Salut le portable !");
void loop(){

The problem is that the second message never print on PortSeriePortable.
I have opened two terminals : one for /dev/ttyACM0 and one for /dev/ttyS0.
When i write a 'a' on one terminal, the second reads another character.
Is there something wrong with the connections (or something missing ?).
Thank you very much.

P.S. : i just have seen that it is necesseray to connect a dual driver/receiver between (type MAX232)...

Please use code tags.

Read this before posting a programming question