Newbie level 3
We have developed a customize board for GSM module using SIM800 IC. When the board was tested with the sim card of Reliance company then it was not detected but when I used the sim card of Idea company then it gets detected and all the AT commands runs using the module. Why only idea company SIM card gets detected and other Sim card are not? The error occured at AT+CREG? command which is AT command for network registration. For working idea sim it shows +creg:0,1 and for reliance it shows +creg:0,5.