Block specific number from outbound route



In IAX we have a route for 9xx ( 900 extensions ) but want to insure we block 911.
The 911 route is before the 900 route which should force it to go to 911 service, but we just had a case where over IAX to this PBX a 911 call was made.
I thought I could use ^911 as one of the lines in the dial pattern, unfortunately that didn’t work. (^ was NOT in syntax from what I read )
Any suggestions?



^ in a regex anchors the match to the beginning, however in trunks the match for a wild card uses _ .

However a call to 911 is better matched as exactly 911 and not _911 which would match any string of characters starting with 911, often we add 9911 to catch some ancient thinking also