Downlink message always the same (Digital Output)


Dear Cayenne users,

I’m using Cayenne to gather data coming from sensors on a STM32 P-Nucleo-LRWAN1 board. The communication protocol is LoRaWAN.
The data from the sensors (humidity, temperature …) is refreshed correctly on the Cayenne interface.

I have also a digital output, a light. When I switch ON–>OFF or when I switch OFF–>ON, the downlink message (in clear) is still the same: 0x15 0x00 0x20 0xD5
So I cannot detect if I have to switch on or off the light on my STM32 board

Are you facing to the same issue? Is it a bug ?

Thanks in advance for your feedback :slight_smile:


Which LoRaWAN provider are you using?


Actility (ThinkPark)


Am I alone to have this issue?


Hi @Aurelien,

Have you seen our downlink documentation?



Yes I have.
I send several uplink messages on which the digital output state is mentioned.
Uplink messages sent: 007326e3016700d2026864030064040100, my digitial ouptut channel is 4 and my led is switched off. The format seems correct.

After a several uplink message exchanged, I receive a downlink message (I switch the led on thanks to Cayenne interface):
(unciphered) Downlink message: 0x15 0x00 0x20 0xD5

At this point, the device should send another uplink message confirming the current state of the actuator.

I cannot reply a correct uplink message because the downlink message does not have a correct format and therefor no sense.

Do I have a wrong spec interpretation?


Tagging @croczey the LoRa master


Any news?
It seems I’m alone to have this issue… pity for me


Hi @Aurelien,

Sorry for the long delay on this issue!

The downlink message you should be receiving is:


In order to determine what is causing the bad data to be sent, can you please send the DevEUI of your device in a direct message to me?

When you added your device to your Cayenne dashboard, you were asked to enter your ThingPark Environment as well as your ThingPark Email and Password


If you entered these incorrectly, it would affect your downlink data encryption. Please confirm that this information was entered correctly when adding your device.

Again, sorry it took so long for a response!