I have successful to execute AT command for list all messages in text mode from usb modem. I used;
"AT+CMGF=1"
"AT+CMGL=\"ALL\""
The return is
AT+CMGL="ALL"
+CMGL: 1,"REC READ","53030303","","2017/07/10 13:04:37+24"
050003FF0301A66FB93C0FCABFEB72103AEC26CFCB7410F95D9E83DC6FBA625E87C3DF723A285
CA7BFDB617A7A0C9A97E9F4B4FB3C7781B2EF3AC85D2E9341F43788FC06D1D165D0BC4CA7A7DD
E739A81D76D7C36C76DEA530BEE5A0A4935A943A8B549D022A7F9BD3EC32C8196E977520D1110
A4A3AA945A9B34815298250A70E243AC3D36E7A59EE2ED345
+CMGL: 2,"REC READ","53030303","","2017/07/10 13:04:37+24"
050003FF030214C6B71CD46C4E750AA8FC6D4EB3CB2067B85DD681444728A8D99C8A1450F91B9
FD781DC75365B017DCBE93A90BBCE662BAA52A60E2442D3E970DDEBD56ECFC7AEB33CDC2E97DD
70F4DB5D768DDFEDD7BC2CB7B3CBF4F9ABDD9E8B1441A85307129DE1EDF65CA480B2CBE179196
44FCFD37450FE5D9783DCE5B0BC3CA7838ED021C8FC9683D0
+CMGL: 3,"REC READ","53030303","","2017/07/10 13:04:37+24"
050003FF0303CA6C38
+CMGL: 4,"REC READ","740502437424","","2017/07/12 13:08:17+24"
Enjoy 4GB Internet Pack at only 179 Taka (Validity 7 days) To START dial
*121*3084#. For details visit www.grameenphone.com
+CMGL: 5,"REC READ","740502","","2017/07/12 20:28:21+24"
We are sorry to inform you that your current balance is not sufficient to
avail the offer. Please recharge and try again.
OK
Here 1,2,3 number messages are multipart. I have tried to decode this on a online converter https://www.diafaan.com/sms-tutorials/gsm-modem-tutorial/online-sms-pdu-decoder/ But it is not decoded. So, of course it is not in PDU format. I want to know, what is this format called and how to decode it, any link or else, please...