My modem works perfectly with my PC through Hyperterminal. My micro also outputs the string perfectly to Hyperterminal. However, my micro and modem connected together does nothing, the modem is not processing AT commands from the micro. I am outputting using the STK500 rs232 port as well as directly from a breadboard, both don’t work. Im confused. What should I do?
The modem transmits on RxD and receives on TxD (see the hardware manual). That might be the cause of your problem.
Leon
maybe full hw flow control is needed?