If you are using the Android RIL then I would suggest AT commands as it would the be the cleanest thing opening a port to the unit and sending AT commands to it.
Hi, can you please provide a typical sequence of AT commands to set up a EM7455/7430 modem for cell data connection? I am using a AT&T or Verizon SIM card.
Ensure modem is registered (on AT&T or Verizon) and then give AT!SCACT=1 to start the data connection. The host’s network manager should setup the host network interfaces automatically or you can use dhclient to set up the interfaces.