Recently I was part of a wilderness SAR training event where there were drone-based FirstNet cell tower deployed to provide emergency personnel with cellular communications in remote areas.
Perhaps I am the lost hiker that is being search for in this scenario, would I be able to place an emergency call through this network?
Would emergency services be able to detect my "ping" (assuming I had a GSM phone) without a FirstNet SIM?
FirstNet is a federally supported USA based national emergency cellular network (segregated network) provided by AT&T and is GSM based, the drone deployment was being tested for SAR use in remote areas.
This question comes from me noticing that my personal phone did not have any indication of service, although I did not explicitly place a 911 call to test an emergency, but the FirstNet device had full bars and had all your usual 4G services available.
[This is explicitly about the USA, but answers related to other areas with similar emergency cell network arrangements are ok too]