🚀 go-pugleaf

     Ringing in North America is a 90 Vac 20 Hz voltage. This is enough
to make your eyes water (I speak from experience).

     Line voltage (when not ringing) is a nominal 48 Vdc. Be careful
if you do use this as a source for any sort of equipment other than
a 'phone. If you pull more than a few milliamps, the equipment in the
phone office will respond as though the phone is off-hook and after
a short time (if no dialing takes place) it will bring up an alarm.
This is a low priority alarm so it may take them some time to get round
to testing it but when they do, they will detect the current drain and
could do something like a) cut off your service (actually, when the
alarm activates in the central office, the voltage is cut off at that
time).
b)Send a repairman around to your home (unlikely)
c)Just leave it as it is (you have no service anyway until you remove
the cause of the problem).

                                 Pete