Overnight, after thinking about your query, I realized you are more likely talking about the allstartlink telephone portal.
And I don’t have a answer for you if so, but was going to post you a link to the set-up info, but I could not locate it in my short time this morning. You might try the wiki or a search though this board to come up with a answer. Or wait for a knowledgeable reply as I have never used the ASL phone portal.
(i use sip and iax trunks)