I think what KLD is saying is that sometimes installers will "hide" the step-down transformer in the phone room. You can use a 66 block to put the power on the appropriate pairs. This technique keeps both the transformer and adapter/splitter thing out of the user's way.

That would explain why the customer was sure that no transformer was involved, yet clearly one had to be in order for this thing to work.

"Press play and record at the same time" -- Tim Alberstein