I send SMS successfully from the SIM900 and the SIM5320 val. The problem is that each SMS deduct credit from my airtime balance. I have SMS-bundles loaded and have tried 3 different mobile companies SIM cards, but all only deducts my airtime at 0.85c per SMS. I used the AT command sendATcommand("AT+CMGF=1", "OK", 1000); // sets the SMS mode to text.
Any suggestions?