What is CREG command meant to be?

Knowledge Base Serial
1

Deal community,
i m working on a firmware where the modem connection wait for a proper value returned by CREG command before start the call (+CREG: 0,1 which is home or +CREG: 0,5 which is romaming).
Is this control really relevant? I tried to skip it and i realized the connection can be established anyway but it seems less “stable”…
Thanks in advance for you help guys

2

Hi,
Did you test 2G or 3G network? AT+CREG? is available for GSM network. AT+CGREG? is available for GPRS and UMTS network. AT+CEREG? is available for LTE network.
It is recommended to query th state of registration firstly before establishing the data connection. As it is needed to ensure registering the network. You can also refer to our AT manual for more details.

3

Thanks for you reply Aaron but i still don t undestrand:

  1. what registration means exactly
  2. what happen if i start an ATDT while not registered?
4

Hi,

  1. what registration means exactly
    —When receiving +CGREG: 0,1 or +CGREG: 0,5 ，It means that the module has registered the network.
  2. what happen if i start an ATDT while not registered?
    —If the module doesn’t register network, it will fail when establishing the data connection.
    Please see the more details from At manual.
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