dave wrote:

On 05/29/2014 10:41 PM, Sjouke Burry wrote:


They hook your phone wires through a dsl unit in the
switch room. That means, that even with the input wires
broken or disconnected, the outgoing wires from the
dsl unit still carry the dsl signal.
So, yes ,your scenario is quite possible.

Here the DSL is sent over the POTS twisted pair from a box on the next
block, thus negating the "maximum" distance problem with using a 3KHz
distribution system for 10Mhz or more signals.

The real reason for those RTs (Remote Terminals, a Central Office in a
box) is the lack of useable copper pair capacity from the old big
building COs. Not only has there been a lot of growth in population
density, but much of that old copper infrastructure is in bad shape and
many pairs in it are unusable.

One big problem with those RTs is the lack of backup power. They have
batteries which will hold them for eight hours or so when new, and a lot
less in a few years of baking in the sun and freezing in the winter.
Unlike big building COs they do not have permanently installed backup
generators.

The Telco has towable generators to theoretically back up the RTs,
however the ration of RTs to generators is large and a big storm can
both exhaust the generator supply and also make towing them to some RT
locations difficult with flooding, downed trees, etc. Cell service is
now more reliable than land lines, since the cell sites do have
generators and fuel supplies to last at least a few days.

As for DSL working and voice getting a busy signal, remember that it
does not take a short to take a line "off hook", rather it takes a
certain amount of current flow which means that a corroded damaged cable
could provide a partial short enough to take the line "off hook", but
not prevent the DSL from working to at least some extent.