Unsolicited uplink data messages


I am working on an end device.
Most of the time the join process completes successfully - though I see an alarming number of times where it doesnt. I am hosting a gateway myself while developing.
I am using the LR1110 development board connected to a Nordic development kit.
Firmware version 1.0.7

The issue I am trying to wrap my head around is that after a successful join I see unsolicited upling data messages.
This has started after I implemented sending data earlier today. See the below picture for an example.

I could successfully see the data I transmitted earlier. I then stopped sending data and only joined the device. But the unsolicited messages kept showing up.

The message come in some 20 seconds after joining and sometimes more messages will show up with 10 seconds intervals consisting of just 2 bytes. On those 2-byte messages no port is listed.

The content of the larger package is very similar from time to time, only a few bytes change. One byte ( the 4B in the picture ) seem to be an increasing counter.
The 2-byte messages change content every time.

I can add that I have successfully received data from TTN.
However receiving can only happen a short while after joining as no events seem to be happening a short while after joining. It seems it could be in conjunction with some of those messages received in TTN…

Any tips and hints are highly appreciated.



An update.

I learned that the device had stored some DM ‘configuration’.
However after setting the DMInfoInterval to 0 and DMInfoFields length to 0 I am still seeing an incoming message on port 199 ( the DM port ) some 18 seconds after joining.
And more data after another 8 seconds.

It doesn’t make sense to me that the modem should send unsolicited messages.
Mind you that I am very new to LoRa and I am just hoping for a perfectly valid reason as to what is going on…

Also - I am having issues receiving data. I am expecting to be able to receive data after having joined - but I can’t. It can only happen shortly after the join process completes.
I am currently looking into that too.


As part of network management, automatic-data-rate (ADR) requests and responses are exchanged between the network and the device. I think this typically happens just after joining and probably at some regular interval after that (about once every 30 or 40 uplinks or so?).

The ADR responses from your device will show up in the MQTT uplink data stream too, they appear as empty data packets, you should just ignore them. Besides being typically 0-length on the MQTT uplink data stream, you might also be able to recognise them by their fport number, which is 0 (I think).

Data coming in on other ports (1…223), is just your device sending regular data, i.e. not something that the network has anything to do with.

Thank you for your reply!

The 2-byte messages I am seeing could be ADR responses. In the image I provided last it shows “Link ADR accept received”. There is no port information on the data received as can be seen in the image.

I am sure that the other unsolicited traffic I am seeing is caused by the LR1110 in some way.
I was expecting to be able to turn it off but haven’t so far had success with that.
I guess I can live with that for now. And the messages can be kept on a separate channel.

I’d still like to understand why I can’t turn those DM messages off.

And my downlink issue could stem from the fact that I can only schedule downlink messages on the TTN network - I suspect that any outgoing scheduled messages will be sent when incoming traffic is received.

I guess I should try to find protocol documentation so I could decode the incoming messages.

Thanks again.