Hi 
I'm trying to access an URL by HTTP with a SIM800L module using AT commands.
I'm using this sketch to comunicate between the Arduino Terminal and the SIM800L.
#include <SoftwareSerial.h>
SoftwareSerial mySerial(3, 2); // RX, TX
void setup()
{
// Open serial communications and wait for port to open:
Serial.begin(1200);
mySerial.begin(1200);
}
void loop() // run over and over
{
if (mySerial.available())
Serial.write(mySerial.read());
if (Serial.available())
{
while(Serial.available())
{
mySerial.write(Serial.read());
}
mySerial.println();
}
}
The SIM800L is powered with a 3.7V battery, with the grouds shared between the Arduino and the SIM800L.
The APN, USER, PASSWORD for the TELCEL GPRS access is good, and I checked them with the company.
The TELCEL company affiermed me the GRPS INTERNET acces is activated on the chip I will use.
I'm using TELCEL company, located in Mexico. Unfortunatly I w'ont going back to france since a time so I can't try with a Bouygues o SFR SIM. I'm obligated to make the tests with a TELCEL chip.
After learning a little bit about the AT commands, i'm trying these commands and I obtain this result:
AT
ATE0
AT+CVHU=0
ATI
AT+CIPSHUT
AT+CGATT=1
AT+CSTT="wap.itelcel.com","iesgprs","iesgprs2002"
AT+SAPBR=3,1,"CONTYPE","GPRS"
AT+SAPBR=3,1,"APN","wap.itelcel.com"
AT+SAPBR=3,1,"USER","iesgprs"
AT+SAPBR=3,1,"PWD","iesgprs2002"
AT+SAPBR=1,1
AT+CIICR
AT+HTTPINIT
Here, everything is good, I obtain corrects answers from the SIM800L.
Since yesterday, IT IS IMPOSSBILE TO PASS THIS LINE :
AT+HTTPPARA=”CID”,1 ----> ERROR
Before I was getting OK, but now I obtain ERROR.
Question : Is the SIM800L module is damaged? Is there a way to reflash a new firmware?
Before when I can pass the AT+HTTPPARA=”CID”,1, I was using these commands:
AT+HTTPPARA=”URL”,”www.m2msupport.net/m2msupport/test.php”
AT+HTTPACTION=0
+HTTPACTION:0,603,0 ----> ERROR
Error 603 - DNS Problem. That's why I can't understand what's happening here.
I tried to set manually the google DNS but I get ERROR.
I obtain the public IP of the SIM800L. So i think it is connected to Internet.
I'm totally lost, I d'ont understand what can happen here...
Regards.