Cannot connect to “au LTE 4G” network (PLMN is 44050) with EC25J module


Our Japan team is testing EC25J module and following issues are observed.

ISSUE #1: The SIM LOCK is invoked after using non-Softbank SIM.
ISSUE #2: Cannot connect to “au LTE 4G” network (PLMN is 44050).

ISSUE #1 is due to EC25J product specification.
If connected to net by using a SIM other than Softbank, then SIM LOCK(Network Subset Personalization Facility Lock) will occur.
After this, it’s not possible to do LTE connection until it is unlocked.
It’s possible to do UNLOCK by sending AT command.

ISSUE #2 is occurring due to au(KDDI) LTE network mechanism.
In the old type au 4G LTE network (PLMN=44050), IMS area registration failure will occur and LTE connection will fail.
Connection can be made possible by disabling IMS registration.
This issue will not occur with au VOLTE network (PLMN=44051).

Please guide us to resolve this.

Thank You,

Dear Sudarshan,
Thankd for your inquiry in Quectel forum.
About your issue, could you help to confirm the module’s firmware version with ATI command firstly, then we can help you to check the issue. Thanks!

Dear Kyson,

Thank you for your valuable support.
Kindly check the AT command response below.

echo ATI > /dev/ttyUSB3

Revision: EC25JFAR06A05M4G

echo AT+QGMR? > /dev/ttyUSB3


Thank You,

Dear Sudarshan,
Thanks for your updating. For your issue, you can try to upgrade the module firmware to have a try. Please email to tp get the latest firmware package and upgrade tool.
If it is still have the issue, it is better to provide your test AT log to us, then we can help you to confirm the issue. Thanks!