Data transfer between GPRS modem and Remote server

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Suganiya

Joined: 18 Apr 2009
Posts: 1

18 Apr 2009 11:40 gprs data transfer

hi,

i am new to GPRS communication, but i hav worked in appcation using GSM.
now i want develop application to transfer data between GPRS MODEM and a server kept in remote place. can anyone help me how to initialize the modem with GPRS mode for file transfer.
Crying or Very sad

even i hope in my application i dont need internet pages to be accessed just want to send and get data from remote sever database.

thanks
Suganiya

GSM Man

Joined: 15 Apr 2009
Posts: 357
Helped: 46
Location: New Jersey, USA

18 Apr 2009 17:49 gprs server

Here's the commands you need to send. In the example below '>>' indicates data you send to the module, while'<<' indicates data returned from the module. This example is for connecting through the AT&T/Cingular network. You'll need to get the APN, user name and password for the network you are using.

First you need to open a PDP context.

Code:

>> AT+CGATT=1 - Attach to GPRS Service
<< OK

>> AT+CGDCONT=1,"IP","wap.cingular" - Define PDP Context (cid, PDP type, APN)
<< OK

>> AT+CDNSCFG="208.67.222.222","208.67.220.220" - Configure Domain Name Server (primary DNS, secondary DNS)
<< OK

>> AT+CSTT="wap.cingular","wap(at)cingulargprs.com","cingular1" - Start Task & set APN, User ID, and password
<< OK

>> AT+CIICR - Bring up wireless connection with GPRS - THIS MAY TAKE A WHILE
<< OK

>> AT+CIFSR - Get Local IP address
<< 10.190.245.172 - returns IP address assigned to your module
<< OK

>> AT+CIPSTATUS - Get Connection Status
<< OK
<< STATE: IP STATUS - returns status of connection, needs to be 'IP STATUS' before you can connect to a server

After you have context, you need to make a connection to the server and then send your data.

Code:

>> AT+CIPHEAD=1    - Tells module to add an 'IP Header' to receive data
<< OK

>> AT+CDNSORIP=1 - Indicates whether connection request will be IP address (0), or domain name (1)
<< OK

>> AT+CIPSTART="TCP","www.google.com","80" - Start up TCP connection (mode, IP address/name, port)
<< OK
<< CONNECT OK    - Indicates you've connected to the server - IT MAKE TAKE A WHILE FOR THIS TO BE RETURNED

>> AT+CIPSEND    - Issue Send Command
<< >          - wait for module to return'>' to indicate it's ready to receive data
>> GET / HTTP/1.1 - Send data - this example is an HTTP request for the default page
>> Host: www.google.com
>> Connection: Keep-Alive
>> Accept: */*
>> Accept-Language: en-us
>>
<< data from server returned - Server will return data here

kiranbdvt

Joined: 03 Jun 2009
Posts: 2

03 Jul 2009 13:40 data transfer through gprs

HI GSM man,

thank you for the info. could you kindly let me know how i can collect the data at the server side( server side coding ) when its not an HTTP request? i have a problem. i am developing a web based remote data logger through GPRS.

GSM Man

Joined: 15 Apr 2009
Posts: 357
Helped: 46
Location: New Jersey, USA

03 Jul 2009 15:50 gprs modem

On the server side you have several options depending on the type of server you are running. You can store the data in a text file, XML file, database, Spreadsheet, etc. The code below is written in VBScript and is for a Windows server running ASP:

Code:

<%@ LANGUAGE=VBSCRIPT %>
<% Option Explicit%>

<%
If Err.Number <> 0 then
   Response.Write(Err.Description)
   Error.Clear
End If

Dim data_string, file_System, file_path, file
data_string = Request.QueryString("Data")
if data_string <> "" then
   Set file_System = CreateObject("Scripting.FileSystemObject")
   file_path = Server.MapPath("Data\LogData.txt")
   Set file = file_System.OpenTextFile(file_path, 8, True)       ' Open File for appending (8)
   file.WriteLine (data_string & vbCrLf)
   file.Close
   Set file = Nothing
   Set file_System = Nothing
   response.write("OK")
else
response.write("No Data")
end if
%>

You can remove the 2 'response.write' lines if you don't need confirmation on the GSM side.

On the GSM side you need to change the first line of your 'CIPSEND' command to include the page name and request data. For example, if the ASP page is named 'LogGprs.asp' and your data is '123456' the first line should be:

Quote:

GET /LogGprs.asp?Data=123456 HTTP/1.1

A good web site for information on server side scripting is: http://www.w3schools.com/

GSM Man

Joined: 15 Apr 2009
Posts: 357
Helped: 46
Location: New Jersey, USA

03 Sep 2009 14:47 send data to local ip address

You need to contact to service provider and get a plan that allows you to accept incoming connections. When you have that you will be given a public IP address by their server.

kejuqeju

Joined: 03 Sep 2009
Posts: 2
Location: Indonesia

04 Sep 2009 18:14 gprs modem data transfer

oh.. i see..
i'll try it. but i think it's hard to do because i don't think the provider will give me that plan.
how bout this.. if i send data via GPRS to a real IP, can i pull back some information or anything from the application that runs in the server? because i see in your previous post there is command GET .... and after that the server give back some information. maybe i can put or set something in the server's application that can be collected by SIM300?

btw i tried the command GET / HTTP/1.1, but there was no response at all. in the server side i got just "GET / HTTP/1.1" string.
why is that?

thx for your help Smile

GSM Man

Joined: 15 Apr 2009
Posts: 357
Helped: 46
Location: New Jersey, USA

04 Sep 2009 18:42 send data with gprs to server

kejuqeju wrote:

how bout this.. if i send data via GPRS to a real IP, can i pull back some information or anything from the application that runs in the server? because i see in your previous post there is command GET .... and after that the server give back some information. maybe i can put or set something in the server's application that can be collected by SIM300?

Yes, you can do that - we have several commercial applications on both Ethernet and GSM that use that technique.

kejuqeju wrote:

btw i tried the command GET / HTTP/1.1, but there was no response at all. in the server side i got just "GET / HTTP/1.1" string.
why is that?

Did you include a blank line and the CTRL-Z? You may need to send the entire header - not just the "GET" line. Many servers will reject a simple request like that as being invalid.

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mpch_elec

Joined: 22 Jul 2009
Posts: 24
Location: Tehran,Iran

05 Sep 2009 5:48 receiving data from gprs modem

Hi friends,
I want to send data with GPRS.
My Modem is Mc39i for Siemens.
i connect to gprs with atd*99***1#
but i don't know what i should be do when connect to gprs.
how can i send data...

rus40

Joined: 15 Aug 2009
Posts: 5
Location: Bulgaria

16 Sep 2009 16:17 gprs for remote data transfer

Hi,
what will happen if the Gprs connection suddenly will i gonna loose data and is there any AT command to prevent this?

MartinLintzgy

Joined: 26 Aug 2009
Posts: 2
Location: Ireland

19 Nov 2009 16:23 Re: Data transfer between GPRS modem and Remote server

Hi,
I am stuck on this.
Using sIM300, trying to GET the homepage of a remote server for testing.
Eg Yahoo.
Problem is :- Where is the data ?

Here is hyperterminal log.
AT+CREG?
+CREG: 0,1
OK
AT+CGATT=1
OK
AT+CGDCONT=1,"IP","internet"
OK
AT+CDNSCFG="62.40.32.33","62.40.32.34"
OK
AT+CDNSORIP=1
OK
AT+CSTT="internet"
OK
AT+CIICR
OK
at+cifsr
10.36.124.132
AT+CIPSTATUS
OK
STATE: IP STATUS
AT+CIPHEAD=1
OK
AT+CIPSTART="TCP","www.yahoo.com","80"
OK

CONNECT OK
AT+CIPSEND

> GET /index.html HTTP/1.0
Host: www.yahoo.com

SEND OK
<No Data>
CLOSED <after a minute or so>

...And yes, i am sending out "\r\n" at end of the GET line
then another "\r\n" before the ^Z
The sim card has credit, and is enabled for data.
I have tried all manner of combinations for the GET command and html header.
i either get nothing, or i get a
+IPD1360:HTTP/1.0 400 Bad Request
Content-Type: text/html; charset=UTF-8
Content-Length: 1350
Date: Thu, 19 Nov 2009 15:17:23 GMT
Server: GFE/2.0
X-XSS-Protection: 0

Ayone any idea what i am doing wrong ?

-martin

GSM Man

Joined: 15 Apr 2009
Posts: 357
Helped: 46
Location: New Jersey, USA

19 Nov 2009 17:02 Re: Data transfer between GPRS modem and Remote server

Two things to verify...
1 - The end of the header of your request must be a blank line - make sure there is no space or other character on the last line. Your request must look like this (where CR & LF are Carriage Return & Line Feed):

Code:

GET /index.html HTTP/1.0CRLF
Host: www.yahoo.comCRLF
CRLF^Z

2 - Some servers are particular about the end-of-line character sequence. They should be Carriage Return and then Line Feed. If you send Line Feed and the Carriage Return some servers will not accept your request.