Most of the phones that we are using are S500’s with the EXP100 expansion unit.
We have BLF keys for all our staff on the expansion unit. When they are on the phone, the light is red. When they are off the phone, the light is green. So far so good.
The problem - if a call comes in, all lines blink and we can’t tell if the staff are on an active call. The only way to resolve this so far has been to disable Call Waiting. We don’t really want to do that because sometimes they are waiting for an important call and still take other calls while waiting.