Router phone knows what 3CX instance to provision too

[Hebz]

We have deployed a fair few X4U-V2 phones used as routers phones now, but I am curious as to how the Fanvil phone knows what 3CX instance it belongs too after adding it to the user in the 3CX admin portal. I am assuming there is some sort of Fanvil device manager that 3CX talks too in order to achieve this, but can't find anything definitive online. I haven't had a chance to packet trace one of these phones yet but am just curious as to how it picks up the correct 3CX instance without me entering an auto provisioning URL.

 

[TheodorosG_3CX]

This is implemented with the RPS server using the unique MAC address of the device.