system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How can you make an emergency call when you have zero signal?
gpt
if you have literally no signal, then you can't. But if your phone can connect to a different provider's tower (roaming) it can place an emergency call and your phone may not show a usable signal. It will usually be able to do this even if you have roaming disabled on the phone.