SIM Card issues of product prototype using EC21-AU

IoT Modules LTE Standard Module
1

I posted a question of SIM card detection problem in EC21-AU module. It always reports error “SIM Card Not inserted”. Unfortunately, nobody replied any solution of the question. Maybe there are similar questions in the forum. The answers cannot get help for my case anyway.

By checking the PCB layout, the traces of USIM_DATA and USIM_CLK are very close in the layout. Will it be a cause of SIM detection failed ?

Will it be an firmware problem in the EC21-AU ?

I would be grateful if any expert can help me.

Many thanks.

2

1)Please try to replace another SIM card, if the output is the same alarm, it may be caused by your PCB
2)You can also solder the SIM pin of the EC21 out and connect to the SIM card holder and try to read if the card is working

3

Thanks for your reply.

I have replaced by another SIM card. It is the same. I did solder the SIM pins of the EC21 out and connected directly to a SIM card. It is still not able to detect the SIM card. Will the PCB layout problem affect the SIM detection although I soldered the SIM directly to the SIM pins of EC21 ?