American carriers have a different protocol than the EU. The EU (and probably EU derived networks) uses a """secret""" SMS format that's opt-in, but the 911 system works differently.
The 911 feature can be activated fully remotely, the 112 feature is supposed to only activate when dialing an emergency number.
The US one is called E911: https://en.wikipedia.org/wiki/Enhanced_911
>The 911 feature can be activated fully remotely
Source? Even if the phone isn't actively doing a 911 call?
GP likely means any 911 call automatically has geo tracing.
>The dispatcher's computer receives information from the telephone company about the physical address (for landlines) or geographic coordinates (for wireless) of the caller.
Wikipedia links https://propertyofthepeople.org/document-detail/?doc-id=2108... as proof that the E911 feature is used by the FBI to track phones.
Unfortunately, definitive capabilities and constraints of this kind of cellular technology is hard to come by.
Wait wait, so if I know the "secret" SMS format I can text someone's phone and get their coordinates back?
No, the SMS is initiated by the device upon calling emergency, not requested by the emergency service. The standard is called AML.
The format is not secret either, it's just binary encoded.
Ahh OK, well that just sounds reasonable.
I say """secret""" because the spec says that the format should not be published so people can't try to mess with the format, but the first link on Google shows the exact format.
The spec says:
> The AML SMS should not be seen by the caller and therefore should not appear in the SMS "sentbox" of the smartphone. This is to avoid any customer confusion and to avoid making the format of the message widely known. In addition, there is also a potential privacy concern in storing the location of an emergency call from the handset, which could be seen by others.
The AML SMS gets triggered by software on your smartphone when you dial an emergency number. You cannot use it to obtain someone else's location.