Internet working without setting APN while using different carrier sim card

Hi there,

I am using an EC21-AUT module and running it on an embedded Linux System (Ubuntu). I am using ppp to access the network. Something weird happened to my units. As the unit accepts different carrier SIM cards and it did successfully ping to an IP, in the case when APN settings remain unchanged.

Debugging I have done so far:

  • AT+QMBNCFG=“Autosel”^M^M

  • +QMBNCFG: “AutoSel”,0^M

  • AT+QMBNCFG=“List”^M^M

  • +QMBNCFG: “List”,0,0,0,“ROW_Generic_3GPP”,0x05010814,201703231^M

gives the previous APN setting but it was not matched the current SIM card inserted.

gives the info of the current SIM card inserted.

I am wondering how did the unit able to access the network with an incorrect APN?


Not all networks require a valid APN. I recall using “porkchop” successfully with Optus many years ago, when the APN didn’t seem to matter.