why I receive m=2 ( USSD terminated by network ) in GSM/GPRS module?

hi.
I bought a GSM/GPRS A6 (Ai-Thinker) module.
I can work with it correctly.
but when I want to see the sim card’s balance in it, It gives me bad result.

  1. my sim card language is english
  2. I used AT+CMGF = 1 and/or AT+CMGF=0 with AT+CSCS=“GSM”
    but when I wrote AT+CUSD=1,“1411#”,15 , I received the following unreadable answer:
+CUSD: 2, "Cy™œ¦ë@6Û,—%¥Rèú¼ê@0PR*Á@äp~îÓfºJJ¥ ˆÎÏ]Òò¸œ¶—Att$RAã7¹<a½
Í ü».a™Ãö·<M/ƒæi÷¹,a‰ó yÙMN»Ï tzr‡Ûeý
                                        
ÂÙp6P¬£¾Ûa÷" ,15

Also:
I used from the following AT commands to give ussd answer as HEX :

AT+CMGF=0 , AT+CSCS=“HEX” , AT+CUSD=1,“1411#”,15

BUT , the received hex answer is not valid (is not readable by online PDU converters). why???

+CUSD: 2, "4379999CA6EB4036DB2C970325A55217E8FABCEA403050522A05C140E4707EEE021DD
366BA0E064A4AA52018881CCECF5DD2F2B89CB6974174741924155241E337B93C07BDCDA0FCBB2E0
799C3F6B73C4D2F83E669F7B92C0789F3A079D94D4EBBCF20747A0E7287DB6510FD0DC2D9703650A
C06A3BEDB61F71C" ,15

My question:

why I receive number m=2 in this structure?while I expect that receive m=0:
+CUSD: [,,]

where :
m:
0 no further user action required (network initiated USSD-Notify, or no further information needed after mobile initiated operation)
2 USSD terminated by network

Step 1. put the sim into a phone and try the keypad string 1411#. Does that get a response? If yes, then its just time to fix the module commands, if no, perhaps USSD isnt supported on your network. (Im assuming it is, since you already seem to have the command string for your network).

If you got a response on the phone, then try the following on the module:

AT+CMGF=1
AT+CUSD=1,"1411#"

(thats what i used on a sim808 module)

scrumfled:
Step 1. put the sim into a phone and try the keypad string 1411#. Does that get a response? If yes, then its just time to fix the module commands, if no, perhaps USSD isnt supported on your network. (Im assuming it is, since you already seem to have the command string for your network).

If you got a response on the phone, then try the following on the module:

AT+CMGF=1
AT+CUSD=1,"1411#"

(thats what i used on a sim808 module)

thank you for your reply.but your suggestion seems doesn't work.
I'm sure that 1411# is correct.
Your code is for sim808, while I have an A6 module (following link)

is there anyone who worked with this module,exactly?

Just to be clear, you've confirmed the string works using that exact sim in a standard mobile?

Its probably worth sending an sms to the module and seeing if you can read that.

Hi,

If you paste those HEX code to: SMSTools3 PDU Converter

USSD Entry/Display GSM 7bit packed UCS2 Cell Broadcast (whole PDU)

4379999CA6EB4036DB2C970325A55217E8FABCEA403050522A05C140E4707EEE021DD
366BA0E064A4AA52018881CCECF5DD2F2B89CB6974174741924155241E337B93C07BDCDA0FCBB2E0
799C3F6B73C4D2F83E669F7B92C0789F3A079D94D4EBBCF20747A0E7287DB6510FD0DC2D9703650A
C06A3BEDB61F71C
( Padding as defined on GSM 03.38 version 5.6.1 (ETS 300 900) page 17 )

You wil get:
USSD/User Data without length information
Alphabet: GSM 7bit

Credit: 66399 IRR. WOW: 0 IRR 0 days. Gift:0 IRR 0 days.Receive the RBT codes of your favorite singer by sending his name to 8686 150Tomans
Length: 139

Kind regards,
Ana

Just elaborating on @anacota4’s answer

Going to this link helped me SMSTools3 PDU Converter

please see my included image, it took a while to figure out…