911 center: Okay, what is the phone number of the phone you are testing (so we know which inbound call to disregard)?

Your argument stems primarily from that point.

The purpose of contacting them is not to identify what phone number will be making the call. The purpose of contacting them is to ensure they are not currently in the middle of a mass casualty incident that you don’t know about.

They don’t care what number you will be making the call from. They care that they have the time and resources available to take it. If your test call is successful, you will tell them that it was a test call.

As for your argument about not having a phone to make the initial call, it’s 2026, not 1926. You have a phone, it’s in your hands right now, and you’re using it to read this.