Thank you Joshua!
I've been helping building the hardware for the front door access for years and I prefer to volunteer that effort rather than pay money for stuff like what you linked. But if we wanted something like that, I think we could build it pretty easily with stuff we already have laying around.
What I'm hoping for with a phone number is to make it so that people can call from their own phones to get to sudoroom, so that even if they can't find the front door but they have the number from the meetup website, they can call and get guidance to find us and then get in the proper door.
I'm concerned that a video link system like what you linked would be more trouble than it would help with...otherwise would could build one.