Types of Emergency Services
Zoom Phone supports two types of emergency services. The type you use depends on whether you want the system to automatically detect a user's location or whether you prefer to assign addresses manually.
PSAP stands for Public Safety Answering Point. A PSAP is the call center that receives emergency calls (such as 911 in the US). When an emergency number is dialed, the call is routed to the nearest PSAP, where a dispatcher answers and dispatches the appropriate first responders (police, fire, or ambulance). The objective of emergency services configuration in Zoom Phone is to provide the PSAP an accurate address so responders are dispatched to the correct location.
Dynamic Emergency Services
With dynamic emergency services, a default emergency address is manually assigned to a user's phone number by an administrator. When that user places an emergency call, the system sends the address that has been pre-assigned to their number. The address remains fixed until an administrator or the user updates it — it does not change based on the user's physical location.
How the address reaches the PSAP depends on the region:
U.S. and Canada (Zoom's PSTN calling): The address is sent directly inside the emergency call itself using a protocol called PIDF-LO. The PSAP receives the address immediately as part of the call — no extra lookup is needed.
Rest of the world (Zoom provided PSTN numbers): The emergency address configured by the administrator is pre-registered with Zoom's native carriers ahead of time. When the user places an emergency call, the PSAP receives the caller's phone number and performs a lookup in the carrier's database to retrieve the address that was registered for that number. No PIDF-LO is sent in this case. Zoom-provided PSTN numbers are available in multiple countries — this model is not limited to the U.S./Canada.
BYOC numbers: For customers using Bring Your Own Carrier (BYOC) numbers, the customer is responsible for working directly with their carrier to update and maintain the emergency address associated with each number. Zoom does not send any address information to BYOC carriers.
Dynamic emergency services are appropriate for users who work from a fixed location (e.g., a permanent office or home office) and whose address does not change frequently.
Nomadic Emergency Services
With nomadic emergency services, the system automatically detects where a user is at the moment they place an emergency call and reports the correct address for that location. This is ideal for hybrid and mobile workers who move between offices, floors, buildings, or home locations.
The detection works by matching the user's network connection data (such as Wi-Fi access point, IP address, or network switch port) against a list of locations that an administrator has pre-configured in Zoom. When a match is found, the system knows which location the user is in and uses the address for that location.
How the address reaches the PSAP depends on the region:
U.S. and Canada (Zoom's PSTN calling): The user's own phone number (DID) is used as the caller ID, and the detected location's address is sent directly inside the call via PIDF-LO. The PSAP receives the address immediately. For users who do not have their own phone number (extension-only users), a number from the Emergency Number Pool is temporarily assigned as their caller ID, but the detected address is still sent via PIDF-LO.
Rest of the world: When the system detects the user's location, it selects the ELIN (Emergency Location Identification Number) that has been assigned to that location and uses it as the outbound caller ID. The PSAP receives the call, sees the ELIN as the caller ID, and looks up the address that was pre-registered for that ELIN in the carrier's database. The address associated with the ELIN must be provisioned with the carrier when the administrator first configures the location in Zoom.
Summary: Dynamic vs. Nomadic
Number of personal locations
Unlimited
Limited to user's DID count
Activation speed
Near-real time
Up to 10 days (carrier address update)
Extension-only users
Fully supported
Not recommended, but supported
Address delivery
PIDF-LO (direct in call signal)
Phone number used as caller ID
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