This process requires you to register all sensor hardware elements installed on the unit board. Then you must assign the sensors to the concrete unit. This step can be replaced with an automatic process via to_be_deployed feature.
The to_be_deployed feature allows you to set a unit into a special to_be_deployed state. In this state, the unit is requested to deliver its list of sensors. Upon successful retrieval of the list the state is cleared.
The to_be_deployed state can be set anytime.
When the unit connects the gateway and sends its registration packet, the reply (configuration packet) includes G-bit (send_info). It instructs the unit to send another registration packet with a complete list of installed sensors.
If the list is sent without a gateway request, it is still accepted, but the unit must be in the to_be_deployed state.
Obviously, the packets are accepted if and only if the unit's PIN is equal to the PIN registered in the gateway database. We strongly discourage you to install and run units without PIN, because this feature could allow an attacker to execute a simple DDoS on the gateway database.