Cellular connection watchdog

Raspberry Pi Network HATs 3G/4G&LTE Base HAT
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I’m using the 3G-4G/LTE Base HAT with a EG25-G. I followed the ECM tutorial as that was listed as the go-to on the store page citing the pending retirement of Sixfab CORE, but another tutorial I’ve since found says ECM may not be compatible with this modem… There is also the QMI interface version that I’m just reading about, and now I’m not sure which one I should be using.

My only requirement is to have a reliable self re-connecting cellular connection for a [very] remotely deployed Pi.

The ECM cellular connection is working great here at home for a couple of weeks now, but what neither tutorial gives me is a sense of how robust this connection is. It re-establishes on restarts fine, but what if it drops for another reason like cell coverage downtime or periods of spotty signal due to tower maintenance or interference etc…?

I bought the Quectel modem as the Telit ECM tutorial contains a note stating that manual intervention is required if the internet connection is “lost for any reason”, however questions remain:

  1. Is there some kind of watchdog we can deploy to run through commands and get the connection back? Is the modem doing this internally? How did CORE do it?
  2. Does Sixfab recommend ECM over QMI today?

Thanks in advance!

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ECM vs. QMI – Which One to Use?

  • ECM Mode: Automatically reconnects as long as there is coverage. It is simple and reliable for most applications.
  • QMI Mode: More program-friendly, allowing manual control over network connections.

How to Handle Disconnections?

Since you’re looking for a stable, self-reconnecting connection, we recommend sticking with ECM, as it will automatically reconnect when the network is available.

If needed, you can implement a watchdog script to check the connection and restart it if required.

@trelaf Let us know if you need further guidance!