However, there are some assumptions made. It is assumed that one already knows how to register ATA ports generally. There is an additional step not mentioned in this document, which is a change that must be made to the default Skinny Call Control Protocol (SCCP) configuration on the ATA. This change is to enter only a dot (.) in the SID0 and SID1 config fields of the ATA.
With this done, and the directions in the document mentioned, the ATA registers successfully.
Note: There is an additional step required in order to have the second ATA18x port register. This requires manipulation of the ATA MAC address. The the leading two digits must be removed, 01 must be added to the end and the dots must be repositioned to conform to MAC address format xxxx.yyyy.zzzz).