[jjnoakes]

This is definitely true. I remember being able to quickly press and release the hangup button on a single phone and if I was quick enough the other person would remain on the line. I don't recall exactly where the threshold was, but I believe it was around a half a second or so.

[ThinkingGuy]

I remember being able to hang up the phone in one room, run to the next room, and pick up the phone and continue the conversation. My friends and I did this on several occasions. This was in the Atlanta area, in the late 1980s.

[eep_social]

Rapidly pressing and releasing the hang up button simulates pulse (as opposed to tone) dialing used by rotary phones.