RAK3172 versions and region configuration

LPWAN Modules / EVBs
1

Hello,

I am struggling a bit understanding RAK3172 versions. I have an evaluation version of the RAK3172 (module mounted on a PCB with a SMA connector for antenna) that I used for testing my system. The code to control the module via AT command was written by my predecessor and it seems he setted the frequency to 433Mhz. So I guess the version of the chip is the one supporting EU433.
I have developed an integrated version of my system with a RAK3172 directly mounted on my PCB so I wanted to test that the RF routing was ok. But by mistake I used the version RAK3172-8-SM-NI (it was the only one avalaible on Digikey).

First, I noticed that their is no marking of the version on the module how to know which one is soldered on a board?
Second, I tried using the AT+BAND=? command to know the available band on my module but the command returned AT_MODE_NO_SUPPORT.
Third, is their a hardware difference between the different version or is it only the firmware on the module that is different?
Finally, Can I make the first module I have (EU433) with the second (EU868) communicate together in P2P mode?

Thanks a lot for your help!

Arthur

2

(1) Marking on the module

Just RAK3172 on the label ==> compatible with 8xx and 9xx MHz frequencies
RAK3172 and somewhere a (L), (LI) or (LP) on the label ==> 4xx MHz frequencies

(2) AT+BAND works only in LoRaWAN mode. It does not work in P2P mode

(3) Hardware difference between the RAK3172 and RAK3172-L versions.
There are two differences:
One difference is the RF path matching components.
Second difference is a resistor inside the module that tells the firmware whether it is a high frequency or low frequency version.

The second difference is read by the module during bootup and allows only the correct LoRaWAN regions and LoRa P2P frequencies to be set.

Final answer
You cannot communicate between a low frequency module and a high frequency module.

3

Hello Bernd.

Thanks a lot for this thorough response, all is very clear now!

Regards,

Arthur