[WaltStuart]

It was my understanding decades ago—that even the older landline phones could be switched on as a listening device if the authorities decided to do it. Even when it was on the cradle.

[missthethunder]

“It was my understanding decades ago—that even the older landline phones could be switched on as a listening device if the authorities decided to do it. Even when it was on the cradle.”

I remember that too.
It was suppose to be better
to take it off the hook.

Maybe the dial tone was to loud.

[tang-soo]

It was my understanding decades ago—that even the older landline phones could be switched on as a listening device if the authorities decided to do it. Even when it was on the cradle.

I remember an episode of 60-Minutes from the 1970s or 1980s that had a story about that very thing. They demonstrated how people with the right equipment could turn a phone that was hung up - ie in the cradle into a listening device. Even though the connection was "open circuit" there was enough induction that subtle vibrations were still available to be picked up. Never saw that technique ever mentioned again until today. :)