dave wrote:

The Phone Company doesn't use shielded cable for baseband audio.


No, but they use twisted pair and they can still pick up a lot of RF.
I've seen over 5 volts of RF on phone lines at AM radio stations that
were wired with 'station wire' instead of twisted pair. The radio
station audio was louder than either party on the line could talk. The
fix was to rip out everything, run 25 pair twisted cable to localized
terminals and use short runs to the phones. There was still some common
mode RF, but at least the lines were usable since it no longer caused
the volume limiter to go into continuous conduction.


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.