<![CDATA[AtomDTU NB-IoT not detecting SIM card]]>Hi, I have tried two different ATOMDTU/NB-IoT modules and two different Sim cards but AT commands show Sim not detected. Any advice?
see details from AT test:

ati
SIM7020G R1910
OK

at+gmm
SIM7020G
OK

at+gmr
1910B03SIM7020G
OK

at+gsn
86151xxxxxxxxxx
OK

at+cgsn
86151xxxxxxxxx
OK

at+cpin?
+CME ERROR: SIM not inserted

See does not detect sim card

also LED status is:
red=on
blue= quick flash once per second

Thanks

]]>https://community.m5stack.com/topic/3552/atomdtu-nb-iot-not-detecting-sim-cardRSS for NodeFri, 13 Mar 2026 08:43:54 GMTTue, 31 Aug 2021 02:48:41 GMT60<![CDATA[Reply to AtomDTU NB-IoT not detecting SIM card on Mon, 11 Oct 2021 20:35:17 GMT]]>@felmue Thank you Felix!

]]>https://community.m5stack.com/post/15101https://community.m5stack.com/post/15101Mon, 11 Oct 2021 20:35:17 GMT<![CDATA[Reply to AtomDTU NB-IoT not detecting SIM card on Sun, 10 Oct 2021 11:15:48 GMT]]>Hi guys

to set the APN you could try to add an Execute code block with the following content:

dtu_nb.send_at_cmd("AT+CGDCONT=1,\"IP\",\"your_apn_here\"")

Please note the string quoting \" and replace your_apn_here with the one you intend to use.

Thanks
Felix

]]>https://community.m5stack.com/post/15088https://community.m5stack.com/post/15088Sun, 10 Oct 2021 11:15:48 GMT<![CDATA[Reply to AtomDTU NB-IoT not detecting SIM card on Thu, 07 Oct 2021 10:50:06 GMT]]>@gmang same here, I also need to change the APN from UIFLOW, did you already solved it?

]]>https://community.m5stack.com/post/15073https://community.m5stack.com/post/15073Thu, 07 Oct 2021 10:50:06 GMT<![CDATA[Reply to AtomDTU NB-IoT not detecting SIM card on Tue, 31 Aug 2021 16:10:18 GMT]]>I also noted there is no way to set the APN details using UIFlow.
I see that using M5Burner one can set the apn using the configuration button on Core, but not on UIFlow_Lite.
Any advice to add APN setup and still use UIFlow

]]>https://community.m5stack.com/post/14779https://community.m5stack.com/post/14779Tue, 31 Aug 2021 16:10:18 GMT<![CDATA[Reply to AtomDTU NB-IoT not detecting SIM card on Tue, 31 Aug 2021 16:06:28 GMT]]>@felmue
RESOLVED: I had the sim card backwards. even though there is a big picture of how to insert it, i still inserted it cut-side first out of habit.
Thanks for pointing it out.

]]>https://community.m5stack.com/post/14778https://community.m5stack.com/post/14778Tue, 31 Aug 2021 16:06:28 GMT<![CDATA[Reply to AtomDTU NB-IoT not detecting SIM card on Tue, 31 Aug 2021 07:09:47 GMT]]>Hello @gmang

have you inserted the SIM card in the correct orientation? According to the second picture here the orientation seems to be up side down and the cut edge towards the outside (which for me was a bit counter intuitive.)

Thanks
Felix

]]>https://community.m5stack.com/post/14771https://community.m5stack.com/post/14771Tue, 31 Aug 2021 07:09:47 GMT