How is that even legal.

While quite frightening, how could you even test this? You can't just make test calls to 911, can you?

(I'm actually somewhat interested in the answer... I have a use-case, and the seeming inability to test is a bit worrying)

You can schedule a 911 test call. "Test calls can be scheduled by contacting your local 911 call center via its non-emergency phone number." [0] More info here:[1]

[0] https://www.911.gov/calling-911/frequently-asked-questions/ [1] https://www.nasna911.org/home

Phone makers (and even their supply chain partners) operate their own in-building cell networks with carrier-type hardware, and extensive debugging and observability, including simulation of multiple towers and location.

It wouldn’t get you 100% E2{ for 911 testing, but it does let you develop and test the stack extensively before taking it to the real world and scheduled testing coordinated with 911 call centers.

Haven't tried it myself, but this official-seeming website suggests that you can schedule a test call ahead of time with your local 911 call center.

https://www.911.gov/calling-911/frequently-asked-questions/#...

I'm pretty sure Google can buy a femtocell to simulate local mobile network of their own.