A non-linear transformation including a plurality of non-linear logical operations is masked to a second or higher order. The apparatus has an outer tubular portion which may be installed, in a single trip into the main wellbore, in a straddling and sealing relationship with the junction, and an inner tubular structure sealingly and removably received within the outer tubular structure. Preferred embodiments address two distinct types of impairment that are unique to VoIP: packet loss and speech clipping in time. 164 numbers are maintained as IP multimedia routing numbers which are utilized for mapping to or otherwise associating with called party URIs. In this way, a determination can be made if any of the targets are out of plumb.