Some problems about GPRS

Ardiuno Compatible shields

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Jacket Chen
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Some problems about GPRS

Post by Jacket Chen » Wed Dec 12, 2012 10:23 am

Q: I just received an GPRS shield v1.4 from Seedstudio. I'm trying to do like
in WIKI and it's not working. If I send something through SSCOM32E from wiki
page, I received 00 00 00 00 (hex) and not "OK". What's wrong with that in
GPRS shield ?

That is the problem. I don't see nothing in SSCOM32E. If I send "AT", the module should response with "OK" and not "00 00".
You write it in your WIKI, about setting "AT+IPR=19200" and "AT", and the response SHOULD be "OK", but it is NOT. My response is "00 00" (hex).
I cannot see "OK" in the screen.

A:There are something errors with your baud rate setting.You need find your baud rate and reset it again.

1)Edit your demo on Arduino ADK:
void setup()
{
GPRS.begin(1200); // the GPRS baud rate
Serial.begin(19200); // the Serial port of Arduino baud rate.
}
and then,upload it.
Open your SSCOM3.2 port,set it to operate at 19200 8-N-1 and then click "Open Com". you should click the "send new" option,and then send AT command "AT".
whether The modem respond with an OK? If yes,send AT command "AT+IPR=19200",and close your SSCOM3.2,then edit demo "GPRS.begin(19200);",upload it.All finished.

If no,continue testing.
2)Edit your demo on Arduino ADK:
void setup()
{
GPRS.begin(2400); // the GPRS baud rate
Serial.begin(19200); // the Serial port of Arduino baud rate.
}
and then,upload it.
Open your SSCOM3.2 port,set it to operate at 19200 8-N-1 and then click "Open Com". you should click the "send new" option,and then send AT command "AT".
whether The modem respond with an OK? If yes,send AT command "AT+IPR=19200",and close your SSCOM3.2,then edit demo "GPRS.begin(19200);",upload it.All finished.

If no,continue testing.
3) Steps like previous:
GPRS.begin(4800/19200/38400/57600/115200);


Note: when you have finally changed the baud rate of GPRS,please modify the baud rate of Serial port too: GPRS.begin(2400);Serial.begin(2400)//or others.

If you find the right baud rate,you can start to use GPRS shield.Good luck.
Love little, love long.

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Re: Some problems about GPRS

Post by Jacket Chen » Thu Dec 13, 2012 11:59 am

Also, you can use UartSBee to change Baud rate ,and it's more simple.
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Re: Some problems about GPRS

Post by danmoller » Tue Dec 18, 2012 1:52 pm

Hi, I am having similar problems. I tried the process you described, but it still didn't work. Chaning the baud rate to 2400 in the Arduino code gives readble serial output, but when I try the AT+IPR=19200 command, it does not work. Sending "AT" works ok. I cannot delete SMS messages in memory either. It seems the problem is that I cannot enter a command of more than about 5 characters long. It is really wierd. Can you please help? It is really frustrating and I cannot use my GPRS and I really need to.

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Re: Some problems about GPRS

Post by Jacket Chen » Wed Dec 19, 2012 3:41 pm

Hi,could you please post your picture of errors?

And whethter you use SSCOM32E to test?
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Re: Some problems about GPRS

Post by danmoller » Thu Dec 20, 2012 9:51 am

Hi,
Yes I can provide some screenshots of the problems soon. I get the same results using both SSCOM32E or the Arduino Serial monitor.

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Re: Some problems about GPRS

Post by Jacket Chen » Mon Dec 24, 2012 2:30 pm

hi all,there are some friends first come to our shield,and don't know how to use it with Arduino Mega.Following picture is the connection.
Image
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Re: Some problems about GPRS

Post by danmoller » Sun Jan 20, 2013 6:54 pm

Hi Jacket,
Sorry for the delay. Please see the attached screenshot. I used the solution as suggested above - in the demo code I used a baud of 2400. Then, my first command was "AT", which I received an "OK. Then my second command was AT+IPR=19200 as you can see in the screenshot. However, as a response I received "AT+920". The solution doesn't work for me and I get strange behaviour which I change the demo code back to 19200. It seems that the shield cannot receive an AT command of more than 2-3 characters - it get's jumbled. (?). Can you please help - this is really frustrating and I cannot use my shield.
Cheers
Dan

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Re: Some problems about GPRS

Post by danmoller » Fri May 31, 2013 9:59 pm

Hi again,
It's been some time. I have since tried with multiple Arduino's and they all give the same results - after I type "AT+IPR=19200" I get a return of "AT+920". It must be something wrong with my Seeedstudio GPRS shield. It must be broken...? What can I do? Can you please help?

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Re: Some problems about GPRS

Post by Jacket Chen » Mon Jun 03, 2013 11:41 am

Hey , whether you have modified the program ? And maybe you have your own program? Could you show me the demo?
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Re: Some problems about GPRS

Post by tiobel » Fri Jan 10, 2014 5:53 pm

Hello,

I´me having exactly the same problem. Did any one found a solution?

Regards,
Hugo Gomes

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