A9 Not registering on the network

[sharmabhimanyu]

Hi,
We are using the A9 development board as part of an IoT proof of concept.
Our A9 module is unable to register on the network, despite reporting a network strength of 12.
The network in question is Airtel and we operated the device in multiple locations to rule out any network issues.
The device was powered from the micro usb port with a 5v 2amp power bank as the power source.

[KaranRajPradhan]

Hi @sharmabhimanyu, are you using the A9 with AT commands(on factory firmware) or are you flashing a custom firmware built on top of the GPRS_C_SDK provided by AiThinker?

In any case, can you provide more information on how you're doing the network configuration?

[sharmabhimanyu]

Hi @KaranRajPradhan, we are running custom firmware on top of sdk.

We have traced the issue to the SIM card. While the SIM card was working perfectly in a mobile phone it wasn't attaching to the network in the A9.
We replaced the SIM and now the A9 is attaching to the network.

Any thoughts on why a particular SIM would not work specifically in the A9?

[tejpochiraju]

@sharmabhimanyu - we have seen this happen on other GSM modems too where data roaming wasn't enabled. Could that have been an issue? It would also help to know what the networks were for the 2 SIMs.

[sharmabhimanyu]

@tejpochiraju - The SIM that did not attach to the network was an Airtel postpaid SIM with roaming enabled ( in the mobile phone)
The Swapped SIM that did attach to the network was a Vodafone prepaid SIM.

Both these SIMs are from the Delhi circle and we are based out of the Delhi circle so data roaming may not have been the issue.

[zeeshanali33096]

@tejpochiraju @KaranRajPradhan So the problem we are facing is the network just drops time to time and the device refuses to connect. As @sharmabhimanyu has already pointed out we are using an IOT Vodafone sim card

I have attached a simple Mqtt demo sketch.
mqtt.zip

[KaranRajPradhan]

@zeeshanali33096 @sharmabhimanyu Can you provide the logs of this network drop you mentioned? Also, is the timing of the drop consistent?

[zeeshanali33096]

Hi @KaranRajPradhan ,

Attaching the logs
Logs.zip

No, We don't think the timing is consistent. But once it drops it rarely connects back