Thanks for the help.
As you mentioned, I used dial delay count 0 in conjunction with ; to avoid # after dialing.
However I am facing another issue with this change. Customer has overlapping extensions. (911, 9115, 9116)so 9115 dial just 911.
so reverted to the original setup, dial delay count 4
User short code N; / +66N / SIP3 requires # after dialing. this is an issue.
Is there any solution for this without changing dial delay count to 0?
(N/+66N ARS N;/N/SIP Trunk works fine as system short code but same doesn't work when used as the user short code, it allows only 4 digit dialing)
Worse case I can request customer to give up 911X but want to know right thing we are doing.