I want to use Drop In for the 3 Echo devices in my house, as intercom type usage.
I do not want to call outside of my household.
I do not have a Smart Phone, so I use the PC Alexa App.
How do I set this up without a Smart Phone??
If a Smart Phone is necessary, why?
In fact, why is a Smart Phone necessary for setting up any Alexa-to-Alexa call?
Does it use my phone line?