Plantronics + Polycom.
Now together as
We have a system with 6 lines. How do I make the line indicators show when a line is busy?
Your question is quite ambiguous - are you on about the BLF function?
If so, there are different perameters depending on what PBX you are using and what Polycom phone software you are running on your phones...
Are you able to give a bit more information on your setup?