eli5 how you could pick up a telephone and hear another conversation(not in the same house)

Question

when i was a kid you could pick up the landline and hit the call button and join whatever conversation was already happening. though i’m reading salems lot right now, and they mention picking up the phone and hearing a conversation from those i know are not in the same home. how did this work???

In: 0

Answer 1

Used to get this with some wireless home phones. They only produced so many frequencies for each model so sometimes neighbours ended up with their handsets picking up the signal from next door.
Otherwise as others have mentioned, could be a party line shared across a couple houses.