Error on checking balance via USSD

Question

I've been trying to check my balance from by 3g modem via AT commands and seem to be stuck.

The device infomation is as follows:

Manufacturer: QUALCOMM INCORPORATED
Model: M6281
Revision: SSD_M6281A-0.0.1 1 [Oct 02 2008 07:00:00]

The modem has USSD capability (advertised and also present in the factory installed dashboard).

I am connecting via putty to COM4 serial port which is my modems application port. All AT commands are working fine but I am getting an error on issuing the following via putty:

AT+CUSD=1,"*111#",15

This returns a simple "ERROR". *111# is my carrier's balance check code. I suspect that there is a formatting error somewhere but I can't figure out where.

Note: If I issue a blank ussd command:

AT+CUSD=1,"",15

then I get an OK (although I later get a response +CME ERROR: retry operation) ... If I write anything within the quotation marks however, it returns an "ERROR".

Have you verified that your modem is registered to a mobile network? Via AT+CREG? — Matt Aldridge, Apr 19 '15 at 13:22

score 8 · Accepted Answer · answered Apr 19 '15 at 14:52

8

Ok, I finally found the way to fix this. Apparently there was a problem in the encoding. Here is what I did:

AT+CSCS="GSM" // change character set to GSM
AT+CUSD=1,"*111#",15 // Issued balance check ussd code

It now works fine.

The default encoding was UCS2, I'd appreciate if someone can share how to convert ussd codes to UCS2 encoding in putty.

answered Apr 19 '15 at 14:52

Andy Mouset

111
1
6

1

Not sure how you modem deals with UCS2. But I have some other Sierra Wireless modems where you just convert the characters to hex and it works. – Matt Aldridge Apr 19 '15 at 16:50
Very valuable information, thanks for providing this as an answer. – hlovdal May 09 '15 at 18:42

score 2 · Answer 2 · answered Apr 19 '15 at 13:01

2

Have you tried issuing request by AT+CUSD=1,"*111#" ? (without last parameter) AT cmmands sometimes differ due to manufacturer implementation.

answered Apr 19 '15 at 13:01

dfgg

21
3

Yes, causes no difference. The blank command gets accepted as well without the last parameter ... so I guess it doen't make a difference in my setup. – Andy Mouset Apr 19 '15 at 13:03
@dfgg Please use comments to ask an user clarification on is question. – β.εηοιτ.βε Apr 19 '15 at 13:05

Error on checking balance via USSD

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