Montblack wrote:

The DSL person explained it to me that each household phone line actually
had two wires in it - DSL uses one, voice the other. I think my "strand"
count is off by a factor of 2(?). More?

The DSL person may have not used precisely correct terminology. The phone
service line (the "network interface"), and the phone wiring within the
house, each have 4 conductors (provided the house was wired within the last
~35 years). By industry standard, these 4 conductors are colored red, green,
yellow, and black, and are paired red-green and yellow-black. The primary
(or only) phone number ("line") in a household will invariably be assigned to
red-green. The secondary phone line will be assigned to yellow-black. In
some neighborhoods, one can get a second phone activated simply by purchasing
a 2-to-1 phone adapter and calling Ma Bell for a phone computer change.

Russell Kent