There are two antenna modes on the Infrafon, active and passive.
If you want to switch to the passive mode you can send the following message:
{
"app": {
"dev": {
"passive_nfc": true
}
}
}
The other way around is with {"passive_nfc": false} .
In order to send this via MQTT, use the topic /ife/device/msgs-down/<device id>.
At last you can write the message into a file, e.g. nfc.json and use the mosquitto-client to conveniently send the message:
mosquitto_pub -L mqtt://your_credentials@mqtt.infrafon.club/ife/device/msgs-down/<device id> -f nfc.json
Note that it could take a few seconds to change the mode from active to passive.