Thanks Hal, yup, saw your thread on the other forum. Don't put the actual telephone company dial tone on the Door King at all. Take a station from the Partner, remove all line appearances, run that to the Door King's input. Run the Door King's output to CO-4 on the Partner. Make sure everyone's Auto Line Select doesn't include line 4.
Visitor presses the Call button, line 4 on the Partner phones rings. You can answer and dial the code to let them in. If you don't have a call in progress, and just want to open the gate, pick up Line 4, you're actually getting Intercom dial tone from the station port, but the Door King is listening for the code to open the gate.
The manuals are easy to find with Google.
