Ams rfid filament recognised

bonjour,
i don’t understand all RFID,
but when i change bobine, i put new filament PETG YELLOW
on GRAY ABS bobine be ended!
but when i synchronize for new project,
he recognise not just quantity,
but PETG and his color!!
how this work?

I assume you have put a yellow PET-G refill on an empty gray ABS spool. Bambu filament refills come with RFID tags, small chips that a sensor in the AMS can detect and read data stored on it. When you removed the empty ABS core from the spool, you removed the ABS chip. When you placed the yellow PET-G refill on the spool you also placed on it a tag that identified the filament as yellow PET-G, and the AMS recognized it and registered the correct data for it. It’s really a pretty neat system, isn’t it?

i really not placed tag for recognize PETG! but i feel that is because in AMS, exist already PETG transluciant tag.but i don’t understand how or exist a link with machin recognize material