Class B device expecting server time after join

I have a Sentrius RS191 sensor end-device and RG191 gateway online, pointed at loraserver-docker, using Semtech forwarder. The end-device’s join requests are being accepted, after which the end-device sends a null packet, and expects that the network server will response with network time. It looks like the server is replying with another null packet, what am I doing wrong? This is my first time working with LoRa, thanks in advance!

here is the block diagram from the sensor’s manual:

I can’t see the mac-commands as the fhdr must be expanded to see the fOpts field. Could you make a new screenshot or screenshots with these fields expanded?

Please note that in order to use Class-B, you need to have a gateway with GNSS / GPS time synchronization. I don’t think has an onboard GPS module.

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Does this image have everything you need?!

Thanks for the quick reply!

Updated the above post, new screenshot shows fOpts. Thanks!

and expects that the network server will response with network time

This is only when the device requests for the time, which it doesn’t do as the fOpts are empty.

I’ve done some reading, and come to understand that the sensor is relying on an application to provide the RTC time in response to what they call “a null packet.” I had – in error – understood that the LoRa network server was responsible for this operation, when in fact it is a custom application made specifically for this sensor.

Also, the Laird RS1xx sensor I’m using is actually Class A.

Thank you for your work and support on this great resource!

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Hi all! I’m using the same sensor Laird RS1XX temperature and humidty sensor and I’m running into the same problem. The gateway that I’m using is Rgx186. Does LoraServer not support this synchronization with this sensors? Because the project is very interesting and it’s a pity that I can’t use this snesor end device. The device tries to join, but unsucessfully :frowning:

See the above comment, LoRa Server does support Class-B, but it seems that your device uses a non-standard way of time synchronization. LoRaWAN has a special mac-commands for this, which is supported by LoRa Server.