If it is a 911 call then I would imagine the location of the call would always be required to help with the emergency services. I couldn't see that giving away

If it is a 911 call then I would imagine the location of the call would always be required to help with the emergency services. I couldn't see that giving away a persons identity as you would naturally expect the 911 call to be the same proximity as the incident being reported. For other types of reports where you have the luxury of calling from an alternative location, you might call the local police or other services rather than the national emergency number (or at least that is how the emergency services are designed to operate in the UK) However if anonymity is your primary concern then you're much better off using a burner or pay phone rather than your primary handset - regardless of the number you choose to dial.