I had a similar issue with an 8X24, I was getting dialtone on a DID card (and wasn't sure I was supposed to, still can't remember if you are)anyway I couldn't get calls in on these DID's. Whenever I tried calling in on the DID's I would get dialtone, and at the dialtone I would dial the Recieved Digits for the DID and the call would route to the appropriate phone for the Target Line. Anyway to make the long story a little shorter after working with the local telco for many hours, they built the DID's as "MF DID's" they changed them to "DTMF DID's" and it worked like magic. The only thing here is I don't recall if we got dialtone on the DID's after this change was made. I don't know if this applies to your customer's situation, but I thought I would share it anyway, hope it helps and if not hope you get it resolved soon. Good Luck