SIM808 Module - Continuous blinking of led (1 blink/sec) - No network established


AIM - To establish network between webpage and Arduino+SIM808

Problem -

I am using a 2G sim which is working fine with my phone but doesn’t work same with with SIM808 module.
The net LED of the Adafruit FONA continuously blinks and I think indicates that the network is not established. I have also tried to update the firmware using SIMcom but the downloading never started.

The following image showes the arduino response:

  1. Can it be a problem with GSM/GPS signal strength?
  2. Voltage input ( Using 5V).

Look forward to your response.

Thank you.

You need to have a power source with 4V and 2A current given to the VBAT pins of module.
The network registration can be issue with band settings also.
What is the BAND setting ? Check AT+CBAND?

Thank you for your response.

After entering AT+CBAND. I got the following result.

<— +CPAS: 2

And also I have changed my battery source.

Q. Can this problem associated with the signal strength of GSM antenna?

When you enter AT+CBAND? you should get the band setting name. Why you are getting CPAS responses?

When I entered the AT+CBAND. I got the CPAS response.

I am not sure what is the problem. Kindly help me to fix the problem.


Thats really strange :smiley:
Did you enter question mark at the end?

Now it’s working. I think there was problem with the GSM antenna.

Thanks for helping.

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