Boss: Add a key: BFS (Her TN) on key 8-14 on his set
Add a key: VCC (Her DN) above that key
Secratary:
Add a key: BFS (His TN) on key 8-14 on her set
Add a key: VSS (His DN) above that key
Now He can "see" the condition of Her set and She can "see" if he is using his phone.
She can Voice Call him anytime, without him having to pick up the handset, and the same with him.
(The His and Hers might be the reverse, but you get it, right!?)
DocVic