Is that only a service that Bandwidth.com offers or would it work on a regular cell network?

I think it depends on the carrier you use, but a lot of other carriers support it.

I'm guessing pretty much all are carriers that are using Bandwidth.com for 911 service.

I've been wondering how to test this, thank you

Completely tangential to testing that the service connects: I have a young child and we've done practice "what do you do in an emergency" things, but are there any "fake 911" type services where a young child can call to practice a 911 call, so they can experience how the operator will talk to them, so in a real emergency it would be a bit less jarring?

Okay, but that's not going through the same paths of a 911 call, is it?

And by that I mean the emergency mode of the modems