Hello,
1. We can't provide an exact dBm answer for this question and we can't guarantee an specific distance at is depends on the environment noise, materials of the walls and door, etc. So, this will need to be tested in the environment that is intended to be used in.
2. Do you mean use two QN9030 to be paired between them ? You have to first make sure you mean the QN9030T which is the one that includes a tag , also if you are trying to pair two QN9030T both of them include an NTAG I2C, this is a passive device , you need a reader to take the information of the tag in the QN9030T. If you are using a reader or a mobile phone to pair the different QN9030s to that mobile phone or reader, that would be possible.
You have to take into account that to get the information of the QN9030T tag through NFC, you need a reader to interact with the device
3. The QN9090, supports eight simultaneous connections, as the QN9030 variant has the same functionality as the QN9090 except for reduced memory sizes of 320 KB embedded Flash, 88 KB RAM, it supports the connections as well.
Nonetheless, besides the radio supports the connections it will also depend on the application footprint in memory considering the stack and the size of the stored information regarding the connections that wants to be stored; for example security level, pairing , bonding, etc. So, you will need to ensure to have enough memory to store the eight connections data in case you decide to use all of them
Hope this helps .
Regards,
Estephania
