All, Is it possible to make the lighted buttons on a 7914 side car (attached to a 7960) light up if that phone is in use? So that the receptionist knows that person is on a call and to not forward a call through? If so how, if not, how can the receptionist know if they are on the phone?
The BLF configuration may be unnecessary for what you want to do here. The need for Presence etc is fairly complicated :( Why don't you just start out with "Shared Lines"
If you have an extension like 5566 at one of the user phones just configure 5566 (try using a "flash only" appearance) on one of the Line Buttons on the 7914. You can also configure a Label for this 5566 Shared Line on the 7914 that shows the 5566 Users name.
When the user at 5566 is on the phone the applicable 5566 Line Button will light up on the 7914 to indicate the line is in use. This may be all you require!
Hope this helps!