Hi I give you more information, can you help me?
I use Arduino UNO, comnnected to a RS232 shield
you can see the connection in this photo
For the rs232 shield i connect the VCC to the +5v of the arduino and the ground to the Arduino Ground
For the trasmission I connect the 7 and 8 pin.
I try all examples found in internet by using serial and serial library, but never.
First question: in the code I need to open one or 2 serial port?
How i can to be sure that I can write and read on the serial?
When I connect the shield to the arduino my pc make a "pling" like i connect a new usb device, is this correct?
thanks for youe support Fabio