I want to be able to connect a true serial (non-USB) port to the rx/tx pins to communicate with the arduino board. I can make this work if I put a rs-232 check tester:
between the cable to the PC and the connector going to pins 0/1 on the arduino.
If I connect bothe sides without the tester, the connection doesnt work.
Does anyone know what I need to address besides pins 0 and 1 for this to work?
Thanks in advance...