Yes, there is a line reversal or voltage change but being a two-wire loop is absolutely nothing like becoming a trunk line.
If you contact outlined numbers, it won't give you a favorable ROI simply because these people have already made it recognized that they don't want contact middle phone calls.
Biancagors
Linkblog von marjoriewarfe über Voip, Audio, Utell, Voice, A, Choice - Social Bookmarking und Web 2.0 Suchmaschine