Hello Everyone,
I need to invoke a web request using Arduino via 3G Modem. I'm still looking for a solution but not found yet.
I'm living in Turkey and Assume that you need a 3G connection, you should buy 3G Modem from Turkcell or Vodafone because IMEI restrictions in Turkey. That's why i'm not using any Arduino 3G GRPS shields or other 3G modules. 
So that the best way is only buying 3G modem from a shop.
Anyway, i bought a Turkcell 3G modem (Huawei E3131C). I changed that HiLink mode can be switched to serial, using http://192.168.1.1/html/switchProjectMode.html after installed win8.1 drivers (you can download HiLink drivers from here, http://drivers.softpedia.com/progDownload/Huawei-3G-Modem-Driver-4200500-Download-123430.html). Now, i can see COM ports to type AT commands. By using Putty, i set 3G modem as serial modem mode, typed AT^U2DIAG=0 (use
AT^U2DIAG=119 to return to HiLink mode). Until here eveything is fine. Now, how can i invoke a web request? For example, i need to call http://www.test.com/helloworld.php
I also try to connect with ZTE MF190 model. but, i couldn't find proper AT commands.
Here is modem information,
ati
Manufacturer: huawei
Model: E3131C
Revision: 22.158.01.00.170
IMEI: 865787013141110
+GCAP: +CGSM,+DS,+ES
Is there any AT commands to call web page? Like in this link; http://www.cooking-hacks.com/documentation/tutorials/arduino-3g-gprs-gsm-gps
// request the url
sprintf(aux_str, "AT+CHTTPACT="%s",%d", url, port);
answer = sendATcommand(aux_str, "+CHTTPACT: REQUEST", 60000);
Thank you.