EC25 - after AT+CGACT=1,1 cannot start PPP with ATD*99***1#

IoT Modules LTE Standard Module
1

Here’s a quick capture from teraterm:

AT+CGACT=0,1
OK
AT+CGACT?
+CGACT: 1,0
+CGACT: 2,0
+CGACT: 3,0

OK
atdt99**1#
CONNECT 150000000

But if PDP#1 is first activated this happens:
AT+CGACT=1,1
OK
atdt99**1#
ERROR

Is this expected behavior ?

This works with other modems and my firmware always issues AT+CGACT to check that the PDP context can be activated because it’s quicker and simpler than waiting for PPP to die during IPCP.

ati0
Quectel
EC25
Revision: EC25AFFAR07A08M4G

2

Dear Sir,
Please provide complete AT capture to us, it is a little strange, generally speaking,the right order is to first activate PDP, i didn’t understand why you execute deactivation command firstly, please refer to the following section:

AT%20CGACT
AT%20CGACT691×543 36.5 KB

2

3

I changed jobs, sorry for no response. Please check my original listing which shows that if I DEACTIVATE the context then ATDT991# works as expected, but if I ACTIVATE the context and then use ATDT99**1# the dial command fails.

If CID 1 is deactivated then ATDT99**1# works as expected (and implicitly reconnects CID #1)
AT+CGACT=0,1
OK
AT+CGACT?
+CGACT: 1,0
+CGACT: 2,0
+CGACT: 3,0
OK
atdt 99 **1#
CONNECT 150000000

If CID#1 is already activated ATDT99**1# fails - this is strange and totally different from the many LTE CAT-1, UMTS and GPRS modems I have used previously.
AT+CGACT=1,1
OK
atdt 99 **1#
ERROR

4

Dear Sir,
If that, please use AT+CGPADDR to check the IP address with deactivate or not deactivate, you can compare the difference.
And use the following command to check whether it return 1, if not, you can set it to 1 to have a try again. Thanks!

image
image712×278 30.9 KB

By the way, you also can change another CID to have a try. Because it will active default bearer after module register on network successful. And the default bearer use CID1. Thanks!

5

Thanks - I will check QCFG.
I have worked with cellular data for nearly 20 years and I have noticed this:
With 3G and 2G context ID 1 (CID#1) is “manually” activated and deactivated by the user application with AT+CGACT or ATDT*99
With LTE CAT1-CAT12 it is not possible to deactivate CID#1 with CGACT - it is an always active default bearer, and it is activated with an IP address as soon as the modem registers.
Is CAT-M and NB-IoT like 2G (application must activate CID#1) or like LTE CAT1 where CID#1 is activated automatically whenever the modem is registered on a network?

6

Dear Sir,
In CATM and NBIOT, it also will active the default bearer automatically. Because they are all evolution from LTE network. Thanks!