Drop the modem for now and see if your Software Serial is working. Connect the TX pin to RX pin. Then write a sketch to send data out the TX and receive it from the RX. Make sure you can transfer data reliably.
Drop the modem for now and see if your Software Serial is working. Connect the TX pin to RX pin. Then write a sketch to send data out the TX and receive it from the RX. Make sure you can transfer data reliably.