I believe that you may be confusing how the “prepend” and the “prefix” fields work. On a dial plan in FPBX when you “prepend” it will add the prepend field info before the entered dial string. When you “prefix” it will strip from the beginning of the presented dial string whatever is in the prefix field.
I posted our setup in the previous post topic thread that you can find here:
There are screenshots of our use of the Dial Manipulation with explanation.
Our use of the 911 and 933 dial string is captured with a separate Outbound Route that is setup as an Emergency Route. The 911 Outbound Route has a higher priority than the regular route.
With the Outbound Route dial Manipulation you have in your example, the only call (using Flowroute and their 11-digit dial string) that should work is if you dial 1NXXNXXXXXX, 911, or 933. All of the others will not yield a valid Flowroute dial string.
Here is a screenshot of our list of Outbound Routes for references regarding 911 handling.
