Ok, here is NEC's explanation:
If you are on a line and dial 911 it looks for an available line and sends the call out on it and hangs up the line you were on. That is the way it is.

So I tell the users not to grab a trunk first but just to dial 911 or 9+911 and the call will go out their line 1 which is what they want.

Now I wander what will happen if you are on a call listening to an auto attendant and you choose option 9 then 1 then 1. Just kidding, there would be no digit analysis going on because the call has already been set up.


GraniteTCS.com