Verify the First Downlink

Send and verify the first MIOTY downlink in KiloCenter — queue a command to a bidirectional endpoint, confirm delivery.

Goal

Queue a downlink command to an endpoint and verify the result.

Prerequisites

• Endpoint registered with bidirectional flag enabled

• Base station connected and supporting bidirectional communication

• At least one successful uplink confirmed (see Verify First Uplink)

Both the endpoint and the base station must have bidirectional capability for downlinks to work.

Send a Downlink via KC-Web

1. Open KC-Web at http://localhost/ (container) or http://localhost:5173 (source dev).

2. Navigate to Endpoints and select your bidirectional endpoint.

3. Use the downlink interface to queue a message:

   • Payload: base64-encoded data (e.g., AQIDBA== for bytes 01 02 03 04)

   • Confirmed: whether to request delivery confirmation

4. Submit the downlink.

Send a Downlink via gRPC (Alternative)

grpcurl -plaintext -d '{
  "endpoint_eui": "<EP_EUI_HEX>",
  "data": "AQIDBA==",
  "confirmed": false
}' localhost:9090 kilocenter.api.v1.KiloCenterService/SendDownlink

Verify the Result

In KC-Web

Check the endpoint's downlink results view for status updates. A successful downlink shows the delivery status and any confirmation from the endpoint.

In Logs

tail -f kilocenter-modules/logs/runtime/kc-core.log

Look for dlDataQue, dlDataQueRsp, and dlDataQueCmp entries -- these represent the three-way handshake of the downlink operation.

Troubleshooting

Symptom	Likely Cause
Downlink stays queued	Endpoint not attached or not bidirectional
"Not bidirectional" error	Endpoint or base station bidi flag not set
No result returned	Base station did not complete the downlink handshake
Payload rejected	Data not valid base64 or exceeds maximum payload size