Common / broadcast frames

Frames any device can broadcast, published under the source device's device/<function>/<instance>/.... The function here is the emitting device's function code, not a fixed value.

All payloads use the standard envelope (data + metadata with lowercase rxdate).

device/<f>/<i>/error/<errorCode> — DTC (published)

Diagnostic Trouble Code. The numeric error code is appended to the topic.

data field	Type	Description
errorCount	int	Number of active errors
errorCode	int	DTC code (also in topic)

metadata: expireAfterSec: 15.

{
  "data": {
    "errorCount": 2,
    "errorCode": 4097
  },
  "metadata": {
    "rxdate": "2026-06-17T14:30:45.123Z",
    "rxTimestamp": 1781793045,
    "expireAfterSec": 15
  }
}

# All errors from any device
mosquitto_sub -h 127.0.0.1 -t 'device/+/+/error/+' -v

device/<f>/<i>/communication-control (published)

data field	Type	Description
communicationOff	bool	Bus communication shutdown flag

metadata: expireAfterSec: 1.

{
  "data": {
    "communicationOff": false
  },
  "metadata": {
    "rxdate": "2026-06-17T14:30:45.123Z",
    "rxTimestamp": 1781793045,
    "expireAfterSec": 1
  }
}

device/<f>/<i>/uid (published)

data field	Type	Description
uid	string	8-byte device UID, 16 uppercase hex chars, no separator

metadata: expireAfterSec: 31536000 (1 year).

{
  "data": {
    "uid": "A1B2C3D4E5F60718"
  },
  "metadata": {
    "rxdate": "2026-06-17T14:30:45.123Z",
    "rxTimestamp": 1781793045,
    "expireAfterSec": 31536000
  }
}

device/<f>/<i>/boot (published)

data field	Type	Description
hotStart	int	Hot-start flag

metadata: expireAfterSec: 31536000 (1 year).

{
  "data": {
    "hotStart": 1
  },
  "metadata": {
    "rxdate": "2026-06-17T14:30:45.123Z",
    "rxTimestamp": 1781793045,
    "expireAfterSec": 31536000
  }
}

mosquitto_sub -h 127.0.0.1 -t 'device/+/+/uid' -v
mosquitto_sub -h 127.0.0.1 -t 'device/+/+/boot' -v