Sending a downlink packet

You can send downlink packets (also called frames) to the device in different ways:

1. From your Application Server, via the Connections associated with your device:

   • TPX IoT Flow connections, as explained in IoT Flow user guide
   • Basic connections, as explained in AS to LRC tunnel interface API

2. From the user interface, as explained in this page.

note

Sending downlink packets from the user interface is not possible while the device is in the Initialization or Suspended states. To learn more, see Device health states.

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1. In the left panel, select Devices, then search for the device you want.

2. Do one of the following:

   • From the device's detailed dashboard, click SEND DOWNLINK at the bottom of the Information widget.

   • From the device list, click in the last column of the table, then select Send Downlink.

3. In the Send Downlink box that opens:

   1. Enter the desired Payload (FRMPayload in LoRaWAN® specification) that you want to send to the device in a downlink packet. This payload must be encoded in hexadecimal format, but it must not encrypted unless your device uses the end-to-end encryption mode (to learn more, see Device attributes). The maximum size is 242 bytes (484 hexadecimal digits).

   2. Enter the LoRaWAN® Port. This corresponds to the FPort in LoRaWAN® specification, associated with the payload, with an integer value between 1 and 223.

   3. If you want the device to acknowledge the receipt of your downlink packet, check the Send confirmed data downlink frame, otherwise leave it unchecked. When this option is checked, upon the reception of this data frame, the device shall transmit an uplink frame with the acknowledgment (LoRaWAN® ACK bit set) at its own discretion.

   4. If you want to empty the current list of queued downlink packets for this device before sending this new frame, check the Flush downlink queue box. This option is only valid for class A devices since the network server does not store downlink packets for class B/C modes. To learn more about the different LoRaWAN classes, see Device classes.

4. Click Validate.

-> The effective transmission of the data payload in a downlink packet is scheduled according to the device class and radio conditions. There may be a longer latency for class A devices, as downlink packets can be sent only after an uplink received from the device. Some devices provide means to force an uplink transmission, refer to your documentation of your device vendor.

After successful sending or abort of the downlink packet containing the data payload, the downlink packet becomes visible in the list of recent packets transmitted to the device.