Extension "h" is not getting executed

Hi All,
I am using Asterisk 1.2 with Digium TE412P interface card. The dial plan is configured in such a way as to execute extension “h” (DeadAGI) when the call is hung up. But here, “h” is executed only when the phone number that I dial is a valid one. If I dial an invalid phone number, the extension “h” is not getting executed. Is there any reason for this. We have another server configured with same Asterisk version but with TE110P interface card. There it works if call is placed in an invalid phone number. The extension.conf is the same. Please do suggest some tips. Thank you.


Kurian Mathew Thayil.