AT Command return has been corrupted

[neumotngayem]

Hi everyone, I am coding the python script for check balance of the sim on module GSM A6, here is my python code:

Code: Select all

port = serial.Serial("/dev/ttyAMA0",baudrate=9600,timeout=1)

port.write('AT+CMGF=0'+'\r\n')
time.sleep(2)
port.write('AT+CSCS="HEX"'+'\r\n')
time.sleep(2)
port.write('AT+CUSD=1,"*101#",15'+'\r\n')
time.sleep(60)
while True:
    if port.inWaiting() > 0:
        reply = port.readline()
        if '+CUSD:' in reply:
            reply = reply[reply.find(',"'):reply.find('",')]
            print reply
    else:
        break
port.flushInput()
port.flushOutput()
port.close()

What I get is like that:

Code: Select all

+CUSD: 1, "D8B41B344687DF20580C879BC56A��MN�&���

How can I fix that

[DougieLawson]

It's returning 7-bit data. You need to convert that to 8-bit to make sense of it.

[neumotngayem]

It's returning 7-bit data. You need to convert that to 8-bit to make sense of it.

Can you suggest me how to do that or the key word to find the solution ?

[DougieLawson]

https://www.google.co.uk/search?q=ussd+decode

[neumotngayem]

https://www.google.co.uk/search?q=ussd+decode

This is how to translate it, but the respone of my is corrupted when I read from serial
+CUSD: 1, "D8B41B344687DF20580C879BC56A��MN�&���

[B.Goode]

Repeating your original question doesn't seem very productive...

What do you expect the returned data to say? What values or quantities are represented by the <?> placeholder symbols?

[neumotngayem]

Repeating your original question doesn't seem very productive...

What do you expect the returned data to say? What values or quantities are represented by the <?> placeholder symbols?

oh no, this situation is like that, I try to get the response of the serial, this is the full respone:
+CUSD: 1, "D8B41B344687DF20580C879BC56AB8586EA6A02E873A500CE79AD56E64450CD4AC8741E7771A4445BFC369903D0C9A36A70A19A8590F83CEEF348818A687153350B31E0691D36334C85E0739D1E131688C7E2B68A0633A9C06D1E56910F2495500" ,15
But as you can see above this is corrupted, some time I can get the full response and some time I can't, I don't know what happend with that

[DougieLawson]

You need to decode it from 7-bit GSM USSD to 8-bit ASCII. It will then print without any errors.

[neumotngayem]

You need to decode it from 7-bit GSM USSD to 8-bit ASCII. It will then print without any errors.

But how come I decode it when the orginal 7-bit GSM USSD data is corrupted already

[DougieLawson]

The stuff you posted on here isn't corrupted. It decodes as:

Code: Select all

Xin chao 0188???????
TKC: 18.357d
1 Mua goi Thoai va SMS
2 Mua goi Data
3 Mua dich vu Nhac cho
4 Giai tri HOT

Note: I've redacted the bit that looks like your phone number.

Online decoder here: http://smstools3.kekekasvi.com/topic.php?id=288