[wodin]

I renamed all of my Echos (except the one that's currently offline) to room names, set them all to drop-in "Only my household" and went home and told the Living room Echo to call the bedroom; and she did! Both Echos started to softly chime and showed a flashing green ring. When Wifey said "Alexa Answer" they stopped chiming, the green ring went solid and we could talk to each other. Since the two echos are within audible range from each other I could tell there was a slight (500 mili-seconds or so) delay, but that's about the same as cell phones or the Nucleus intercom system.

Getting her to stop intercoming (is that a word?) was a bit of a chore as she didn't seem to listen to the wake word, and I had to push the button. And I haven't experimented with connecting to my Alexa app on my cell phone. I don't see a way to initiate a call from the app.