my problem is : after set AT+CMGF = 1 ( for Text mode SMS), everything work well until GSM modem reboot After reboot, AT+CMGF? command return 0 , this means modem need re-config for CMGF parameter.
Please help to save the config value even after reboot. Thanks so much.
The traditional modem way to store configuration settings is through profiles, controlled with AT command AT&W, see my answer for some details about that command. Now if your particular modem supports more than one profile and if the AT+CMGF mode is included is another question, but at least AT&W is what I would start investigating around.
