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Yes, the sending data downlink to a device is supported. It is not on the console right now. You can use CLI to make that happen. The reference can be found via this link, https://docs.aws.amazon.com/iot-wireless/2020-11-22/apireference/API_SendDataToWirelessDevice.html.
Great, thanks!
What happens if I send a downlink message to a Class A device? Does it get sent to the Gateway, and the Gateway sends it to the node the next time the node sends an uplink?
Thanks.
Is this documented anywere? I can't find it.
I have a device that has a Class C device profile (US915-C-OTAA) and when I use SendDataToWirelessDevice to send data to it, it doesn't get sent right away. It's only getting sent after an uplink. Since it's a Class C I would have expected to be sent right away. Am I doing something wrong?
For Class A devices, the downlink packets will be held in AIL until an uplink is seen.
Edited by: russ-awsiot on Mar 14, 2021 10:22 AM
The most possible cause for this issue might be that you are using TransmitMode=1 for the DL. If the device is not acking back in time, the next DL packet cannot get sent until the previous one is time-out. If you need further diagnosis, you can provide more information here and we can further investigate.
Regarding the documentation, I think it is not that detailed regarding the downlink handling yet. The API reference can be found here, https://docs.aws.amazon.com/iot-wireless/2020-11-22/apireference/API_SendDataToWirelessDevice.html. But I guess you already know it. We will keep updating the documentation to have all possible details reflected. Thanks for the feedback.
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Class A devices sleep most of the time. They listen for downlink messages (from gateway to device) only for a short period after transmitting. If a cloud-hosted application sends a command to this device, a significant delay may take place until the messages is received by the device. Because of that, class A devices are typically battery-powered sensors, having a battery time of up to 10 years.