mobileat-commandmodem

CREG, CGREG, CEREG AT commands


I have to control a modem Cinterion ELS61 with a host application. Can anyone tell me in simple words which is the real difference among at+creg?, at+cgreg? and at+cereg? commands? I know that cgreg is related to 2G and 3G radio access technology and cereg with 4G/LTE one, but the actual differences are not so clear and neither the relation with the creg command results. It follows an example from a real case:

AT+CREG?
+CREG: 2,5,"38AD","02531900",7
OK
AT+CGREG?
+CGREG: 2,4
OK
AT+CEREG?
+CEREG: 2,5,"2AF2","02531900",7
OK

What is the difference among the answers to +creg and +cereg? Aren't they quite the same? And by the way, what does it mean that the same cell (02531900) has 2 difference location area codes (i.e. 38AD and 2AF2)? Thanks for the attention


Solution

  • All the +C*REG commands, as you probably know, query the status of the registration to some network.

    The first step is the following categorization:


    +C*REG commands are technology specific commands:


    The reason why different commands are available (even in the same cellular module) is that different registration processes are required for each sub-network.