RAK3172-E : Class C - downlink & multicast - firmware 4.0.6


I have 1x rak3172 module, and I’m testing the last available firmware v4.0.6, and I have done the comparaison with the 3.4.11:

  • The downlink with the firmware 3.4.11, and the class C, from my gateway (milesight UG56) is working well (I’m receiving the payload of the downlink few seconds after the sending). I don’t receive anything with the firmware 4.0.6, with the same configuration (I can receive with TTN, but with class A behaviour (in RX1 period)).
  • The multicast (class C firmware 3.4.11), is also working well (reception by the rak3172 few seconds after). But I can’t configure it for the class C (after join): AT+ADDMULC=C:01020304:01020304050607080102030405060708:01020304050607080102030405060708:869525000:0)

perhaps I misuse the API RAK RUI.

I have searched without success into the forum some duplicates topics.

The firmware 3.4.11 looks to be a stable revision (before the 4.0.6), is it right (or is it the 3.4.2) ? I have notice in the forum that a 48 days bug is present for the 3.5.x revisions, and firsts 4.0.x revisions. Do you know if this bug is also present for the 3.4.11 firmware revision ?

Thank you in advance for your help,

Did you setup the device in TTN as a Class C device?

I tried on Chirpstack. When I declare the device as Class A, even if I set the device itself as Class C, the downlinks are not send immediately.

If I set it in Chirpstack to Class C, the downlinks are working.

About the RUI3 versions, V3.4.2 is quite outdated, but was a stable version.
You can check the status of the versions in the Changelog

IMHO the best to use is V4.0.6, I am using this on a daily basis.

For the multicast, I never used it, but from the example you copied, there seems something wrong with the parameters:

[Class] [DevAddr] [NwkSKey] [AppSKey] [Frequency] [Datarate] [Periodicity]
Your example
C 01020304 01020304050607080102030405060708 01020304050607080102030405060708 869525000 0
Working for me in AS923-3
C 00993357 11223344556677881122334455667788 11223344556677881122334455667788 916800000 0 0

(1) 869525000 is not a valid frequency for EU868
(2) the last parameter, the periodicity is missing

Thank you for your answer.

I think I have found why: TTN use the non standard frequency 869525000 for the RX2 (Frequency Plans | The Things Network), perhaps this why, the rak3172 doesn’t receive anything. The milesight gateway was initialized also with the same default frequency value for the EU868 RX2 for Class C …

I have changed to the frequency 868500000, and in this case, it’s working well …

Do the rak3172 filter or check of the downlink frequency ?

For the multicast :

The writing of the multicast configuration looks strange (and/or the display by LSTMULC). I don’t receive anymore unicast messages (of the Class C) after adding the multicast configuration, and the return of LSTMULC looks corrupt :



For the RX2 frequency, there is a default preset in the firmware. If a gateway/LNS uses a different one, you have to adjust it in the device manually.

For the multicast, I will check with the R&D team. As I said, I never used it.