With traditional 9-1-1 service (also known as enhanced 9-1-1), the phone service is provided and can only be used at a specific location, so your 9-1-1 call is sent directly to the nearest public safety answering point (PSAP).

With VoIP 9-1-1 service (also known as Nomadic 9-1-1 or N 9-1-1), the phone service can potentially be used anywhere with an Internet access, so your 9-1-1 call is sent to an emergency operator to confirm your location before the 9-1-1 call can be transferred to the correct PSAP.