PPP connection drops (NO CARRIER) every 24 hours


I’m using the EC25-E / EC200S-EU modules through UART on a custom STM32H7 board with the lwIP stack.
The PPP connection in data mode works great for weeks and weeks without any problem.

But every 24 hours the PPP connection drops by receiving NO CARRIER. The immediate reconnection is always successful.
Why is that? Is it network or module related?


According to the description, it cannot be confirmed, but in most cases, NO CARRIER is sent by the called party or the network side. Generally, the network will have UE inactive timer. When there is no data within a certain time, the link will be automatically disconnected.

What firmware version are you using now?

Currently we have 230 modules on the field and another 200 on the way. All of them doing the same.
No matter what we do, sending data or not, the behavior is the same. In the normal operation we have an open websocket connection all the time. We are sending reguraly a ping-pong, heartbeat messages and TCP keep-alive every 15 seconds.

One of the module firmware is: EC200SEUAAR01A04M16

We have other minor issues, and we have a hard time to understand and debug them. The AT command interface and URCs not always enough. Is there any other way to debug the modules behavior? On the debud UART or USB interface?

Thank you for your help!

And one more thing to this 24h connection drop.
The 24h is always starts from the module startup.
If I start the module and the data call at 8:00AM, the connection drops (NO CARRIER) the next day around 8:00AM, and the next day around 8:00AM, and so on.

Hi,USB or serial port can be used to debug, please provide your email, I will send the debugging tool QCOM to you.