Emergency Location Identification Number (ELIN)
An ELIN (Emergency Location Identification Number) is a phone number dedicated to emergency calling purposes. It functions as a location identifier in the form of a phone number.
For example, an organization assigns a phone number to the 3rd floor of an office building and registers that number's address with the carrier as "123 Main Street, 3rd Floor." When a user on the 3rd floor dials an emergency number, Zoom uses that dedicated phone number as the caller ID. The emergency dispatcher receives the number, performs a database lookup, and identifies the caller's location as the 3rd floor of 123 Main Street.
When ELINs Are Used
ELINs are used in two main scenarios:
Extension-only users — users who do not have their own direct phone number (DID) need an ELIN to provide a caller ID for emergency calls, since they have no personal number to present to the PSAP
Rest of the world — outside the U.S./Canada (or when using a BYOC carrier for emergency calls), the address cannot be sent directly inside the call signal, so an ELIN is used as the caller ID and the PSAP looks up the pre-registered address for that number
Shared Caller ID for U.S./Canada — in addition to the scenarios above, U.S./Canada customers can configure a shared caller ID for emergency calls. This means that even if a user has their own U.S./Canada phone number assigned to them, the system can use a shared number as the emergency caller ID instead of the user's personal number. This is useful for organizations that require a standardized emergency caller ID across a site or account. Because the address is always sent via PIDF-LO in U.S./Canada, the actual caller ID number does not affect the address that the PSAP receives.
In the U.S. and Canada with Zoom PSTN calling, ELINs are generally not needed for users who have their own phone number, because the address is sent directly via PIDF-LO regardless of the caller ID.
Where ELINs Are Configured
ELINs can be set at the site level in the Zoom admin portal. When configuring a site or a location within a site, the administrator assigns one or more ELINs that will be used for emergency calls originating from that site or location.
Types of ELINs
Three ELIN types are available, each with distinct callback routing behavior.
Dedicated Number
A dedicated number ELIN uses an existing phone number that is already assigned to an Auto Receptionist, Call Queue, or Shared Line Group in your Zoom Phone system. This number is designated as the emergency caller ID for a specific location.
How it works: When a user at that location places an emergency call, the dedicated number is used as the outbound caller ID. The PSAP sees this number and can look up the address registered to it.
Callback routing: If the PSAP calls back on this number, the call routes to the Auto Receptionist, Call Queue, or Shared Line Group — not to the individual user who placed the emergency call. The safety team or receptionist managing that queue must be prepared to receive emergency callbacks and connect the dispatcher with the appropriate personnel.
Temporary Number from Local Emergency Pool
A local emergency pool is a set of phone numbers dedicated to emergency calling at a specific site. These numbers are shared among all users at that site and are temporarily assigned during an emergency call.
How it works: When a user places an emergency call, a number from the pool is automatically assigned as their outbound caller ID. If the PSAP calls back on that number, the call is routed directly to the user who placed the emergency call — not to a receptionist or queue. This callback routing is cached for 2 hours after the emergency call (even if external incoming calls are blocked for the user). After the 2-hour window expires, the cache is cleared, and any callback to that number will receive a "call cannot be completed" message. The number then becomes available for reuse.
Concurrent emergency calls: If a different user places an emergency call while all pool numbers are in use, the system reuses a number from the pool. The callback cache updates to reflect the most recent caller, routing subsequent callbacks to the latest emergency caller rather than the previoU.S.one.
Pool sizing: Organizations must determine pool size based on the maximum number of simultaneous emergency calls anticipated at a given site. This is a life-safety decision — undersizing the pool can result in loss of PSAP callback capability during active emergencies. For sites with fewer than 100 extension-only users, 1–2 pool numbers are typically sufficient. Larger sites should scale accordingly. Critical: When the pool is fully exhausted, numbers are reused starting with the oldest call. The 2-hour callback cache is immediately overwritten to the newest caller, and the previous caller's callback path is silently released with no notification or fallback. In mass-casualty events, earlier callers permanently lose PSAP callback reachability while the incident is still active.
Temporary Number from Account Emergency Pool (U.S./Canada Only)
An account-level emergency pool works similarly to a local pool, but the numbers can be shared across multiple sites within the same account. This option is only available for U.S./Canada.
How it works: Any U.S./Canada phone number can be added to the account-level pool. When a user at any U.S./Canada site on the account places an emergency call, a number from this shared pool is used as the outbound caller ID. Pool numbers may be from any area code; the area code is irrelevant because the emergency address is sent directly in the call signaling via PIDF-LO at the time of the call, ensuring the PSAP receives the correct address regardless of the caller ID's area code.
The same 2-hour callback caching mechanism applies to the account-level pool.
ELIN Summary
Dedicated Number
Per location
Routes to AR/CQ/SLG (not the caller)
Locations with a staffed safety desk
Local Emergency Pool
Per site
Routes to the emergency caller (2-hour cache)
Most deployments — recommended default
Account Emergency Pool
Account-wide (U.S./Canada only)
Routes to the emergency caller (2-hour cache)
Multi-site U.S./CA deployments sharing a common pool
Shared Caller ID
Per site/account (U.S./Canada only)
Depends on configuration
Standardizing emergency caller ID across sites
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