HL7692 CME ERROR in command AT+CGATT=0

IoT Modules Legacy HL Series
1

I am trying to make this command works to establish connection but allways i have the same answer.

+CME ERROR: invalid mobile class

it’s extrange because i can make this comand works once answering “OK” but when i try to send this again. It is sending the error.
The module is HL7692 implemented in a custom pcb. The module is working correctly because i could connect to internet with AT-Commands.
the reason of this question is that i have to send a lot of this command to make this works.
in the devkit pcb this command works always and this error is new for me.

thank in advance & i hope it’s clear enough

¿Anyone knows what could be happening?

2

@meydey,

So just to be clear you are sending at+cgatt=0 to the unit and it is responding with a CME error?

If this is the case I suspect that it is doing this because it is attached to LTE and the cgatt command you are sending is telling the unit to detach from the network which it cannot do without completely coming off it. If the unit were on 2G then it would probably be ok since the circuit switched and packet switched attaches are separate.

Another explanation might be that you have a session set up and running then it definitely will not be able to detach.

Regards

Matt

3

Okey i understand. But what should i do to this well? if at+cgatt is only for detach an dattach from 2G and to 2G conection , right?

So i make a connection to a LTE network i have to detach with another or anothers commandos, ¿What comando i should send?

off-topic: there are one commando that tell us what type of connection is attach? like GPRS, LTE…?

regards
Meydey

4

@meydey,

It might be easier if you just say what you want to acheive?

To answer your last question it technically does not make complete sense really, I have given a couple of commands below which give you a bit more information and hopefully you can judge a bit better.

  • at+cops? will give you the network you are on and with the last parameter giving the tech you are using, so, 0 for 2G, 2 for 3G and 7 for LTE.
  • at+creg? gives you the circuit switched attached status, at+cgreg? the packet switched status and at+cereg? the EPC (Evolved Packet Core) status which is LTE specific. In 2/3G the first two were distinctly separate but in LTE, because it is an all IP network, they are a bit mixed up (trying to keep it simple).

Basically don’t send at+cgatt=0 unless you have a specific reason to do so.

Regards

Matt

5

i want to make a 4G connection but i had a 3G modem that use this command but i am not sure if the commands a re the same or something change.
can help me?

regards

6

Making the connection using 2 3 or 4G is effectively the same, the modem will choose the bearer, application starts the connection and all you will then see are differing speeds depending on the bearer you are on (trying to keep it as simple as possible).

Just don’t send at+cgatt=0 because you are telling the unit to not use the network it is on.

Regards

Matt

7

so, then an at+cgatt=0 and then sending an at+cgatt=1 to make sure the conection is attached is unnecessary?

8

Or just send the at+cgreg? command to make sure it is PS attached which it will do automatically on power up anyway (assuming default settings).

Regards

Matt