@felmue

Hi there,

Now, Module is working correctly there were few issues and solved it step by step. This solution is for someone if they found this post & they need help.

1. USB to TTL convert was not recognizing UART signals transmitted from SIM7020G module. (as it was 1.7V)
2. GND was missing between different module (MOST IMP) (Use common supply maybe PC, SMPS or something else)
3. CR should be there after command.

What I did is add Logic Level Converter module between USB to TTL converter and SIM7020G module.

NOTE: Refer datasheet of IC and do the same connection as shown in datasheet for less garbage data and proper communication.

Thank you so much Felix for your help and efforts.

Hi there,

I have SIM7020G COM.X NB-IOT module and I am trying to connect it with network.

I am using 12V 3A SMPS and DC-DC step down converter (3A max) to drive SIM7020G module. Also, I am using airtel sim card.

AT

OK
AT+CPIN?

+CPIN: READY

OK
AT+CSTT="airtelgprs.com,"",""

ERROR
AT+CSTT="airtelgprs.com","",""

OK
AT+
+CGREG: 0▒▒CI
+CGREG: 2

+CGREG: 0
AT+CIICR

ERROR
AT+CGREG=?

+CGREG: (0-2)

OK
AT+CSQ

+CSQ: 99,99

OK

+CGREG: 2

This is what I am getting in response and I tried to change sim card.

Thank you so much in advance

@felmue

Hi there,

Now, Module is working correctly there were few issues and solved it step by step. This solution is for someone if they found this post & they need help.

1. USB to TTL convert was not recognizing UART signals transmitted from SIM7020G module. (as it was 1.7V)
2. GND was missing between different module (MOST IMP) (Use common supply maybe PC, SMPS or something else)
3. CR should be there after command.

What I did is add Logic Level Converter module between USB to TTL converter and SIM7020G module.

NOTE: Refer datasheet of IC and do the same connection as shown in datasheet for less garbage data and proper communication.

Thank you so much Felix for your help and efforts.

@felmue

Thanks for quick response.

when I was measuring voltage between GND of USB to TTL converter and GND of COM.X module. Multimeter shows 2V. (See the illustration)

But this issue is resolved by supplying power to same power source (My PC).

I want add that when I use two different USB to TTL converters then RX LED is not blinking and that means i am not getting any response.

I think this is due to Rx pin HIGH is 1.7V only and my USB to TTL converter (using CP2102) is not recognizing 1.7V. (Just a guess)

Can you share the converter you are using?

I connected to two USB to TTL converter. One to transmit data and another one to receive the data.
and opened two different serial terminal in PuTTY.

TX LED of one converter and RX LED for another converter is still blinking but there are no data on PuTTY terminal

I also used tera term and Terminal software to verify it.

@jeets said in SIM7020G echoing even after using ATE0:

@felmue

I tried to connect the ground but the problem is there is 2V difference between Ground of USB to TTL converter and Ground of COM.X module.

How should I remove it?

I connected Green PCB and USB to TTL converter with PC (Supplying voltage via USB connector)

I am able to ON/OFF SIM7020G using AT commands but I am not getting any response in PuTTY. There are no echo in UART but also no response from SIM7020G.

I measured voltage over Tx pin of SIM7020G and its 0.9V.

Observation:

I can see both TX and RX LED blinking on my USB to TTL converter whenever I send command but not receiving data on serial monitor.

I have tried different baudrate but the issue is not solved.

Thank you so much to put your efforts and time felix!

@felmue

I tried to connect the ground but the problem is there is 2V difference between Ground of USB to TTL converter and Ground of COM.X module.

How should I remove it?

Thank you

@jeets said in SIM7020G echoing even after using ATE0:

UPDATE:

I tried AT+CPOWD=0 command and netlight stopped blinking. So, I am guessing command is being sent and accepted by SIM.

and also it can be turned on using AT+CFUN=1 command.

However, I am still getting echo in response. How can I get "OK" or "ERROR" or something else?

I don't understand why this is happening. I am using this USB to TTL converter. I changed converters too.

It is not possible to troubleshoot or program efficiently without proper responses from SIM7020G.
Thank you.

UPDATE:

I tried AT+CPOWD=0 command and netlight stopped blinking. So, I am guessing command is being sent and accepted by SIM.

and also it can be turned on using AT+CFUN=1 command.

@felmue

Oh Okay. Let me try

I think I should also include these points.

1. Do I need to connect POWERKEY to STM32 controller GPIO and Pull down it as mentioned in datasheet? (See below attached image)

2. I only connect Tx/Rx in USB to TTL convert as there is 2V difference between GND of COM.X module and USB to TTL converter.

PS: I tried settings in PuTTY but it is not working.

Thank you so much felix for support!

@felmue

Hi there,

I have tested CR,LF and EOL in the end but still getting same issue.

I tried to connect it with easyloader application but it shows "failed". I tried both 1500000 and 115200 baudrate.

What if I upload any latest firmware to sim7020G?