We are testing a RG255C-GL module, firmware RG255CGLABR01A04M4G_A0.004.A0.004.
AT+CREG=? gives ERROR
Many other like AT+QNWINFO too
Can this be a matter of firmware ?
May I have the latest one ?
have you ever checked your sim card? whether it is tested on another module or device? Much appreciation
Dear @Jonathan.wang
Please check whether ? is English characters.
Hi Jonathan
Yes the SIM works fine with any other module (EG25, EC25 RM500Q etc)
Dear @RadeoCom
RG255C doesn’t support these AT command.
You can use AT+CEREG and AT+QENG.
Hi Silvia,
thank you for your answer.
Do you have a manual explaining which commands are and are not supported by RG255C ?
Should I understand that is only able of data for iot ? (no voice, no sms etc)
Dear @RadeoCom
I have sent AT command manual to you via Message, please check.
Dear Silvia,
I’m also trying to create a 4g/5g connection and I’m struggling with the AT-Commands needed.
All preconditions seem to be there but I can’t get the device to register to neither a 4g nor a 5g network.
Could you please share the AT-Command manual for the RG255 with me, thank!
Any maybe you have some hints… 
Best regards,
Fabian
Dear @rpfab
I have sent to you via Message, please check.