INFORMATION RESPONSE AND FINAL RESULT CODE

AT+CGMI <-- Command line entered Nokia <-- Information response OK <-- Final result code
28
Case Sensitivity of AT Commands
In the SMS specification, all AT commands are in uppercase letters. However, many GSM/GPRS modems and mobile phones allow you to type AT commands in either uppercase or lowercase letters. For example, on Nokia 6021, AT commands are case-insensitive and the following two command lines are equivalent:
AT+CMGL
AT+cmgl