jlk53 UNKN is unknown, intl is international, natl is national. If you are set as NI2 the CO is looking for you to tell the switch whether the call in unknown, international or national. If you send unknown and pass the 011 the call will go thru. If you are set as international and send 011 the call will be blocked by the Central Office. What type of CO switch are you connected to? If it is a Nortel DMS they will block the hell out of your calls if not setup properly in the isdn setup message. So if you are able to debug your setup message and see in there that the call was setup with intl and you send 011 it will get block. If you are sending natl with 011 you will get blocked. If you send unknown and have 011 it should go thru. ISDN national 2 is very particular.
If you can not debug your d-channel then any CO tech should be able to put on a d-ch analyzer and look at the setup message to tell you what is wrong. The CO should see the called number plan as isdn telephony rec e164 and the number type unknown, international, national but the pbx has to set the call up correctly. If all else fail numbering plan type unknown type of number unknown and make sure to send the 011