Sim800l Network

Using Arduino Storage
1

Hello everyone,

I'm working on a project using the SIM800L module to establish a GPRS connection. Despite exhaustive testing and troubleshooting, I'm unable to attach the module to the network. Here's a detailed summary of what I've done so far:

  1. Hardware Setup:
  • Verified power supply: I'm using a stable 5V supply with sufficient current.
  • Antenna: Connected and properly positioned.
  • SIM card: Inserted and works perfectly in a mobile phone for data connection.
  1. Software and AT Commands:
  • I'm able to communicate with the module and receive responses.
  • AT commands like AT, AT+CSQ, and AT+CREG? return OK responses.
  • Signal strength is good (+CSQ: 31,0).
  • APN settings are correct: AT+CSTT="java.claro.com.br","claro","claro".
  • The main issue: AT+CGATT=1 consistently returns ERROR.
  1. Attempts to Resolve:
  • Tried different power supplies and capacitors for stability.
  • Ensured correct APN settings matching the carrier.
  • Moved to different locations to ensure network availability.
  • Verified that the SIM card has an active data plan and isn't locked.

Here are some typical responses from the module:
OK
AT+CREG?

+CREG: 0,0

OK
AT+CGATT=1

ERROR
AT+CSTT="java.claro.com.br","claro","claro"

ERROR
Based on my understanding, the +CREG: 0,0 indicates that the module is not registered to the network. I've tried manually registering with AT+COPS=1,2,"72405", but this also results in an error.

Has anyone faced a similar issue or could provide insights into potential solutions? Any help or suggestions would be greatly appreciated!

Thank you in advance!

Best regards, Milton Tofetti

2

Is "72405" your port speed? Are you using, for example, 38400 as port speed?

3

I changed the speed to 115200. As the manual suggests, I still got the same error.
What would be the port speed of "72405"
How should I act on the "AT" command to make the change.

4

Did your try 38400?

5

I changed it to 115200 and now it's working.
Thank you for your help!