# Emergency callback numbers in Webex Calling

Canonical: https://warmtransfer.net/knowledge/webex-calling-ecbn

Last verified: 2026-09-25

In Webex Calling, the Public Safety Answering Point (PSAP) uses the configured emergency callback number (ECBN) when responding to an emergency call placed by a user[^39]. Control Hub provides three configuration choices for a calling entity's ECBN: its own telephone number, the location default ECBN, or an assigned number from the entity's location[^50].

## Configuration in Control Hub

ECBN can be configured for locations, users, workspaces, and virtual lines in Control Hub[^14]. Webex exposes dedicated "ECBN Available Phone Numbers" APIs separately for locations, persons, workspaces, and virtual lines[^2].

* **Locations**: The location ECBN is configured under Management > Locations on the location's Calling tab[^34]. The location default ECBN can be set to either the location main number or an assigned number from within the location[^33]. Control Hub warns when a toll-free number is chosen as a location's main number because toll-free numbers have no emergency service address[^51].
* **Users**: A user's ECBN is configured under Management > Users > (user) > Calling via the Emergency Callback Number entry in the Numbers section[^52].
* **Workspaces**: A workspace's ECBN is set under Management > Workspaces > (workspace) > Calling via Emergency Callback Number in the Numbers section, with the workspace number, location default ECBN, or an assigned number from the workspace's location available as choices[^56]. Control Hub displays a warning when a workspace number or a virtual line is selected as the ECBN[^57].
* **Virtual Lines**: A virtual line's ECBN is set under Services > Calling > Virtual Lines > (virtual line) > Calling via Emergency callback number in the Numbers section[^54].

If a user, workspace, or virtual line has only an extension, the "User's phone number" option does not appear[^23]. The "Assigned number" drop-down lists only entities with an assigned telephone number; extension-only users, workspaces, and virtual lines cannot be chosen as an ECBN[^5]. Furthermore, an assigned-number ECBN must come from the same Webex Calling location as the entity receiving the setting[^6].

An assigned ECBN can belong to another user, a workspace, a virtual line, or a hunt group in the location[^4]. Assigning a hunt group as an ECBN was announced on March 31, 2025[^26], following a developer changelog announcement on December 18, 2024, that added Hunt Group support to the ECBN retrieval and modification APIs effective January 27, 2025[^3]. Once a hunt group is assigned as an ECBN, its phone number cannot be changed to a toll-free or service number[^25]. Cisco warns that when a hunt group serves as an ECBN, the answering agent may differ from, and be unaware of, the original caller, and Call Forwarding or Advance when busy settings can prevent agents from being alerted to a PSAP callback[^24].

When an administrator deletes a user whose number serves as another entity's ECBN, Control Hub issues a warning, and affected entities fall back to their own telephone number if they have one, or otherwise to the location default ECBN[^32].

## Recommendations and Device Behaviors

Cisco recommends providing users with their own telephone numbers to use as their ECBN, and otherwise assigning the number of an actual user so PSAP callbacks reach a person[^40]. Cisco also recommends that every user with non-fixed (soft) devices has a phone number set as their ECBN to direct callbacks to that user[^36]. For soft clients on non-fixed devices equipped with cellular capability, emergency calls are always handed off to the device's native dialer rather than routed through Webex Calling[^8].

Webex Calling does not know or store the emergency service address for an emergency call; the PSTN provider supplies the address, typically through a static mapping to the received ECBN[^35]. WarmTransfer's reading of the sources is that on the non-RedSky path, choosing an ECBN belonging to a different building than the caller will likely deliver the wrong address to the PSAP because the PSTN provider relies on this static mapping[^27]. In addition, WarmTransfer's reading of the sources is that for an extension-only user without ELIN enabled, a callback reaches whoever holds the ECBN rather than the caller, potentially reaching someone unaware of the emergency[^28].

For workspace devices, Webex Calling accepts incoming calls carrying a Priority header marked emergency, and it lifts inbound call restrictions on the device for 60 minutes after an emergency call is placed so the PSAP can call back[^55].

In the US and Canada, 933 serves as an emergency test number to validate 911 configurations without contacting a PSAP; many PSTN providers answer 933 calls with an IVR readback of the asserted ECBN and emergency service address[^1].

## Enhanced Emergency Calling and ELIN

Cisco documents RedSky and Intrado as enhanced emergency calling providers for Webex Calling[^30]. RedSky integration is positioned as an optional mechanism to deliver accurate address information for non-fixed devices[^45]. Enhanced emergency calling with RedSky is available for Webex Calling locations in the US, its territories, and Canada[^42], with Canadian users requiring a RedSky license obtained through Cisco or a service partner[^41]. Verizon training materials direct administrators to configure an ECBN for locations to complete the RedSky enhanced emergency setup[^53].

HELD-capable endpoints for RedSky include Cisco 6800, 7800, and 8800 Series MPP desk phones and Webex App, whereas Poly VVX and Yealink phones are treated as non-HELD endpoints[^43]. For non-HELD endpoints, the RedSky E911 service determines dispatchable locations from the caller ID asserted on the call by matching a DID in Locations or Users[^46]. Emergency calls from MPP phones not discovered via HELD (such as those off the RedSky wiremap) are likewise handled based on asserted caller ID[^44]. WarmTransfer's reading of the sources is that if a non-HELD device asserts an ECBN that lacks a corresponding address match in RedSky, the service probably cannot establish a dispatchable location and routes the call to a relay center[^29]. If the E911 service cannot find a dispatchable location for any calling device, the call is routed to an emergency calling relay center[^47]. Outbound calls route to RedSky only after an administrator toggles on "Route Emergency Calls to RedSky" for the location, which Cisco instructs admins to perform after 933 test calls succeed[^48].

When ELINs are available in the location's pool, Webex Calling uses an ELIN rather than the ECBN for the emergency call:[^19]

* **Precedence**: When ELINs are available in the location's pool, Webex Calling uses an ELIN rather than the ECBN for outbound emergency calls[^19].
* **Pool Management**: Administrators do not assign ELINs directly to users, workspaces, or virtual lines; ELINs are managed as a location pool, and inbound callbacks to an active ELIN route to the user who placed the emergency call[^18].
* **Binding Expiry**: An ELIN remains bound to the caller for a configurable location expiry period of 10 to 1440 minutes (defaulting to 60 minutes)[^16].
* **Platform Interaction**: ELIN is enabled by default across Webex Calling emergency services without separate activation, though Cisco Calling Plan subscriptions require service numbers enabled[^15]. ELIN usage does not alter RedSky or PIDF-LO handling[^21].
* **Unsupported Clients**: ELIN is not supported for Webex Go mobile devices or Single Number Reach[^22].
* **Reporting**: On March 27, 2026, Cisco added CDR fields identifying the ELIN used for outbound emergency calls and inbound emergency callbacks[^7].

## Regulatory Obligations

In the United States, FCC Part 9 defines Automatic Number Identification (ANI) as the calling party identification that may be used as the callback number[^9]. Under 47 CFR 9.3 a dispatchable location consists of the validated street address plus details such as suite or apartment necessary to identify caller positioning[^12]. The FCC's multi-line telephone system (MLTS) regulations encompass network- and premises-based systems, including VoIP, Centrex, PBX, hybrid, and key systems[^13].

47 CFR 9.16(b)(1) mandates that MLTS platforms allow direct 911 dialing without prefixes or trunk-access codes like 9[^10]. 47 CFR 9.16(b)(3) established automated dispatchable location requirements for fixed on-premises MLTS devices as of January 6, 2021, and for non-fixed on-premises devices as of January 6, 2022 where technically feasible, permitting manual or alternative locations otherwise[^11]. To assist with Kari's Law (Public Law 115-127), Control Hub provides emergency call notifications configured per organization or location, which are disabled by default[^38]. Notification emails include the location's main address—which may not reflect where the call originated—and are sent in English only[^37].

## See also

- See also [Webex Calling enhanced emergency calling](https://warmtransfer.net/knowledge/webex-calling-emergency-calling).
- See also [Setting up Webex Calling emergency calling with RedSky](https://warmtransfer.net/knowledge/webex-calling-redsky-e911-setup).
- See also [E911 test calls and validation](https://warmtransfer.net/knowledge/e911-testing-procedures).
- See also [Meeting Kari's Law and RAY BAUM's Act on an enterprise phone system](https://warmtransfer.net/knowledge/kari-ray-baum-compliance).
- See also [Dispatchable location and nomadic user handling](https://warmtransfer.net/knowledge/dispatchable-location).
- See also [US emergency calling regulatory requirements](https://warmtransfer.net/knowledge/e911-us-regulatory).
- See also [Intrado enterprise 911 routing services](https://warmtransfer.net/knowledge/intrado-enterprise-911).

## Applicability

Applies to: Cisco Webex Calling, Cisco Webex App, Webex Calling (Verizon offer), 911 service, and MLTS. Deployments: on-premises and multi-tenant. Sources checked 2026-09-25. RedSky integration is restricted to locations in the US, its territories, and Canada[^42], with Canadian deployments requiring a dedicated RedSky license[^41]. Intrado configuration is documented for US locations[^30]. Administrators do not assign ELINs directly to users, workspaces, or virtual lines[^18]. Hunt group assignment as an emergency callback number was announced in What's new in Webex Calling on March 31, 2025[^26], and the Webex developer changelog entry of December 18, 2024 announced API support from January 27, 2025[^3]. Webex Calling lifts inbound call restrictions on a workspace device for 60 minutes after an emergency call is placed[^55].

## What remains uncertain

- Kari's Law notification ownership when RedSky routing is on (RedSky portal vs Control Hub) is not covered by the sources below.
- How Intrado ERS consumes ECBN and caller ID and confirmation of the release year are not covered by the sources below.
- ECBN behaviour outside North America (UK EU APAC locations) is not covered by the sources below.
- SIP signalling of ECBN toward local gateway and CCP providers (PAI vs From vs other) is not covered by the sources below.
- ELIN pool exhaustion behaviour when all ELINs are in use is not covered by the sources below.
- Webex Go and Single Number Reach emergency calling and callback path is not covered by the sources below.
- Emergency CDR field names for ELIN and callbacks are not covered by the sources below.
- Local gateway Legacy behavior setting that blocks ELIN callbacks is not covered by the sources below.

## Sources

[^1]: 933 is a North American emergency test number that tests 911 configuration without reaching a PSAP, and many PSTN providers answer it with an IVR that reads back the ECBN and emergency service address. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), 'Configure a user's number as ECBN' (933 note). Checked 2026-09-25.
[^2]: Webex exposes 'ECBN Available Phone Numbers' APIs separately for locations, persons, workspaces and virtual lines. Source: [Changelog | Webex for Developers](https://developer.webex.com/docs/api/changelog), Entry dated December 18, 2024, affected API list. Checked 2026-09-25.
[^3]: The Webex developer changelog entry of December 18, 2024 announced that from January 27, 2025 the ECBN retrieval and modification APIs support a Hunt Group in addition to People, Place and Virtual Line. Source: [Changelog | Webex for Developers](https://developer.webex.com/docs/api/changelog), Entry dated December 18, 2024. Checked 2026-09-25.
[^4]: The assigned number chosen as an ECBN may belong to another user, a workspace, a virtual line or a hunt group in the location. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), 'Options for ECBN configuration', third option. Checked 2026-09-25.
[^5]: The 'Assigned number' drop-down lists only entities that have a telephone number; extension-only users, workspaces and virtual lines cannot be chosen as an ECBN. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), 'Configure a user's number as ECBN' and 'Configure a workspace number as ECBN'. Checked 2026-09-25.
[^6]: An assigned-number ECBN must come from the same Webex Calling location as the user, workspace or virtual line it is applied to. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), Option label 'Assigned number from a user's location' / 'from the workspace's location' / 'from the virtual line's location'. Checked 2026-09-25.
[^7]: A March 27, 2026 changelog entry introduced CDR fields that identify the ELIN used for outbound emergency calls and inbound emergency callbacks. Source: [Changelog | Webex for Developers](https://developer.webex.com/docs/api/changelog), Entry dated March 27, 2026. Checked 2026-09-25.
[^8]: Soft clients on non-fixed devices with cellular capability always hand emergency calls to the device's native dialer rather than placing them through Webex Calling. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), 'Non-fixed (soft) devices and ECBN'. Checked 2026-09-25.
[^9]: The FCC's Part 9 definitions state that for 911 systems ANI identifies the calling party and may be used as the callback number. Source: [47 CFR § 9.3 - Definitions (Cornell LII republication)](https://www.law.cornell.edu/cfr/text/47/9.3), 47 CFR 9.3, definition of 'Automatic Number Identification (ANI)'. Checked 2026-09-25.
[^10]: 47 CFR 9.16(b)(1) requires an MLTS to let users dial 911 directly without any prefix or trunk-access code such as 9. Source: [47 CFR § 9.16 - General obligations for MLTS (Cornell LII republication)](https://www.law.cornell.edu/cfr/text/47/9.16), 47 CFR 9.16(b)(1). Checked 2026-09-25.
[^11]: 47 CFR 9.16(b)(3) required automated dispatchable location for fixed on-premises MLTS devices from January 6, 2021, and for non-fixed on-premises devices from January 6, 2022 where technically feasible, with manual or alternative location otherwise. Source: [47 CFR § 9.16 - General obligations for MLTS (Cornell LII republication)](https://www.law.cornell.edu/cfr/text/47/9.16), 47 CFR 9.16(b)(3). Checked 2026-09-25.
[^12]: Under 47 CFR 9.3 a dispatchable location is the validated street address of the calling party plus information such as suite or apartment needed to identify the caller's location. Source: [47 CFR § 9.3 - Definitions (Cornell LII republication)](https://www.law.cornell.edu/cfr/text/47/9.3), 47 CFR 9.3, definition of 'Dispatchable location'. Checked 2026-09-25.
[^13]: The FCC MLTS definition covers network- and premises-based systems including Centrex and VoIP as well as PBX, hybrid and key systems. Source: [47 CFR § 9.3 - Definitions (Cornell LII republication)](https://www.law.cornell.edu/cfr/text/47/9.3), 47 CFR 9.3, definition of 'Multi-line telephone system or MLTS'. Checked 2026-09-25.
[^14]: ECBN can be configured for locations, users, workspaces and virtual lines in Control Hub. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), Section headings 'Configure a location number as the ECBN' through 'Configure virtual lines as ECBN'. Checked 2026-09-25.
[^15]: ELIN is available by default within Webex Calling emergency services with no separate enablement, though Cisco Calling Plan subscriptions must have service numbers enabled. Source: [Configure ELIN for Webex Calling](https://help.webex.com/en-us/article/5oxx10/Configure-ELIN-for-Webex-Calling), 'Overview'; 'Billing information for Cisco Calling Plan'. Checked 2026-09-25.
[^16]: An ELIN stays bound to the emergency caller for a configurable ELIN expiry time of 10 to 1440 minutes, default 60 minutes, set per location. Source: [Configure ELIN for Webex Calling](https://help.webex.com/en-us/article/5oxx10/Configure-ELIN-for-Webex-Calling), 'Configure ELIN expiry time'. Checked 2026-09-25.
[^17]: If no ELIN is available, Webex Calling falls back to the ECBN configured for the user, workspace or location. Source: [Configure ELIN for Webex Calling](https://help.webex.com/en-us/article/5oxx10/Configure-ELIN-for-Webex-Calling), 'How ELIN works'. Checked 2026-09-25.
[^18]: Administrators do not assign ELINs directly to users, workspaces or virtual lines; ELINs are managed as a pool per location, and callbacks to an ELIN in use route to the user who placed the emergency call. Source: [What's new in Webex Calling](https://help.webex.com/en-us/article/rdmb0/What's-new-in-Webex-Calling), March 30, 2026 entry on ELIN support. Checked 2026-09-25.
[^19]: When ELINs are available in the location's pool, Webex Calling uses an ELIN rather than the ECBN for the emergency call. Source: [Configure ELIN for Webex Calling](https://help.webex.com/en-us/article/5oxx10/Configure-ELIN-for-Webex-Calling), 'How ELIN works'. Checked 2026-09-25.
[^20]: ELIN works with Cloud Connected PSTN, premises-based PSTN (local gateway) and Cisco Calling Plan, but a local gateway with 'Legacy behavior' enabled blocks inbound ELIN callbacks while outbound emergency calls are unaffected. Source: [Configure ELIN for Webex Calling](https://help.webex.com/en-us/article/5oxx10/Configure-ELIN-for-Webex-Calling), 'Overview' / 'How ELIN works'. Checked 2026-09-25.
[^21]: ELIN does not change RedSky or PIDF-LO handling: emergency calls still route to RedSky or carry PIDF-LO where applicable, whether an ELIN or an ECBN is used. Source: [Configure ELIN for Webex Calling](https://help.webex.com/en-us/article/5oxx10/Configure-ELIN-for-Webex-Calling), 'How ELIN works'. Checked 2026-09-25.
[^22]: ELIN is not supported for Webex Go mobile devices or Single Number Reach. Source: [Configure ELIN for Webex Calling](https://help.webex.com/en-us/article/5oxx10/Configure-ELIN-for-Webex-Calling), 'Overview' (supported devices). Checked 2026-09-25.
[^23]: If a user has only an extension, the 'User's phone number' ECBN option does not appear; the same applies to extension-only workspaces and virtual lines. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), 'Configure a user's number as ECBN' step 4 and parallel workspace/virtual line steps. Checked 2026-09-25.
[^24]: Cisco warns that with a hunt group as ECBN the answering agent may differ from, and be unaware of, the caller, and that Call Forwarding or Advance when busy on the hunt group can prevent agents being alerted to the PSAP callback. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), Hunt group notes within 'Options for ECBN configuration'. Checked 2026-09-25.
[^25]: The phone number of a hunt group that is assigned as an ECBN cannot be changed to a toll-free or service number. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), Hunt group notes within 'Options for ECBN configuration'. Checked 2026-09-25.
[^26]: Assigning a hunt group as an emergency callback number was announced in What's new in Webex Calling on March 31, 2025. Source: [What's new in Webex Calling](https://help.webex.com/en-us/article/rdmb0/What's-new-in-Webex-Calling), March 31, 2025 entry 'Assigning Hunt Group as Emergency Callback Number'. Checked 2026-09-25.
[^27]: On the non-RedSky path, because the PSTN provider maps the received ECBN to an address, picking an ECBN that belongs to a different building than the caller will likely send the PSAP the wrong address (inferred). Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), 'Specifications' combined with 'Options for ECBN configuration' (more accurate ESA mapping rationale). Checked 2026-09-25.
[^28]: For an extension-only user with no ELIN in use, a PSAP callback reaches whoever owns the ECBN (location default, another user, workspace, virtual line or hunt group) rather than the caller, so the callback may reach someone unaware of the emergency (inferred). Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), Combines 'Options for ECBN configuration' with the hunt group warning; ELIN contrast from cisco-help-5oxx10-configure-elin 'How ELIN works'. Checked 2026-09-25.
[^29]: With RedSky, a non-HELD device whose asserted caller ID is an ECBN that is not matched to an address in RedSky probably cannot get a dispatchable location and would go to the relay center (inferred). Source: [Enhanced Emergency Calling for Webex Calling](https://help.webex.com/en-us/article/av6oo3/Enhanced-Emergency-Calling-for-Webex-Calling), 'Location detection'; 'Enable the E911 service for Webex Calling locations'. Checked 2026-09-25.
[^30]: Besides RedSky, Cisco documents Intrado as a configurable enhanced emergency calling provider for Webex Calling. Source: [Enhanced Emergency Calling for Webex Calling](https://help.webex.com/en-us/article/av6oo3/Enhanced-Emergency-Calling-for-Webex-Calling), Headings 'Intrado' and 'Configure Intrado as an emergency provider'. Checked 2026-09-25.
[^31]: The What's new page lists 'Intrado as an Enhanced Emergency Calling provider for Webex Calling' with a date of July 28, 2026. Source: [What's new in Webex Calling](https://help.webex.com/en-us/article/rdmb0/What's-new-in-Webex-Calling), Entry 'Intrado as an Enhanced Emergency Calling provider for Webex Calling'. Checked 2026-09-25.
[^32]: When a user whose number serves as others' ECBN is deleted, Control Hub warns, and the affected entities fall back to their own telephone number if they have one, otherwise to the location default ECBN. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), 'Deleting key users or numbers'. Checked 2026-09-25.
[^33]: The location default ECBN can be set either to the location main number or to an assigned number from within the location. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), 'Configure a location number as the ECBN'. Checked 2026-09-25.
[^34]: The location ECBN is set in Control Hub under Management > Locations, on the location's Calling tab. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), 'Configure a location number as the ECBN'. Checked 2026-09-25.
[^35]: Webex Calling does not know or store the emergency service address for an emergency call; the PSTN provider supplies it, typically by a static mapping to the ECBN it receives. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), 'Specifications'. Checked 2026-09-25.
[^36]: Cisco recommends that every user with non-fixed (soft) devices has a phone number and uses it as their ECBN so the callback is directed to that user. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), 'Non-fixed (soft) devices and ECBN'. Checked 2026-09-25.
[^37]: The emergency call notification email carries the location's main address, which may not correspond to where the emergency call was actually placed, and is English-only. Source: [Configure emergency call notifications in Control Hub](https://help.webex.com/en-us/article/nj0abhbb/Configure-Emergency-Call-Notifications-in-Control-Hub), Notification contents section. Checked 2026-09-25.
[^38]: Control Hub emergency call notifications, provided for Kari's Law (Public Law 115-127), are disabled by default and can be set for the organization or per location. Source: [Configure emergency call notifications in Control Hub](https://help.webex.com/en-us/article/nj0abhbb/Configure-Emergency-Call-Notifications-in-Control-Hub), Overview and configuration sections. Checked 2026-09-25.
[^39]: In Webex Calling the PSAP uses the configured emergency callback number (ECBN) when responding to an emergency call made by a user. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), Introduction and 'Options for ECBN configuration'. Checked 2026-09-25.
[^40]: Cisco recommends giving users their own telephone number to use as their ECBN, and otherwise using the number of an actual user so the PSAP callback reaches a person. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), 'Requirements and recommendations'. Checked 2026-09-25.
[^41]: Canadian users need a RedSky license obtained through Cisco or the service partner. Source: [Enhanced Emergency Calling for Webex Calling](https://help.webex.com/en-us/article/av6oo3/Enhanced-Emergency-Calling-for-Webex-Calling), 'Requirements for E911 service integration with Webex Calling'. Checked 2026-09-25.
[^42]: Cisco's enhanced emergency calling with RedSky is offered for Webex Calling locations in the US, its territories and Canada. Source: [Enhanced Emergency Calling for Webex Calling](https://help.webex.com/en-us/article/av6oo3/Enhanced-Emergency-Calling-for-Webex-Calling), 'RedSky overview' / 'Requirements for E911 service integration with Webex Calling'. Checked 2026-09-25.
[^43]: HELD-capable endpoints for RedSky location discovery include Cisco 6800, 7800 and 8800 Series MPP desk phones and Webex App; Poly VVX and Yealink phones are treated as non-HELD. Source: [Enhanced Emergency Calling for Webex Calling](https://help.webex.com/en-us/article/av6oo3/Enhanced-Emergency-Calling-for-Webex-Calling), 'Location detection' / 'Deployment scenarios'. Checked 2026-09-25.
[^44]: Emergency calls from MPP phones whose location was not discovered through HELD (not on the RedSky wiremap) are treated based on their asserted caller ID. Source: [Enhanced Emergency Calling for Webex Calling](https://help.webex.com/en-us/article/av6oo3/Enhanced-Emergency-Calling-for-Webex-Calling), 'Enable the E911 service for Webex Calling locations'. Checked 2026-09-25.
[^45]: Cisco's ECBN article positions the RedSky integration as an optional way to give accurate address information for non-fixed devices. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), 'Non-fixed (soft) devices and ECBN'. Checked 2026-09-25.
[^46]: For non-HELD devices the RedSky E911 service determines location from the caller ID asserted on the test or emergency call, looking for a matching DID in Locations or Users and using that address. Source: [Enhanced Emergency Calling for Webex Calling](https://help.webex.com/en-us/article/av6oo3/Enhanced-Emergency-Calling-for-Webex-Calling), 'Location detection'; 'Enable the E911 service for Webex Calling locations'. Checked 2026-09-25.
[^47]: If the E911 service cannot find a dispatchable location for the calling device, the emergency call is routed to an emergency calling relay center. Source: [Enhanced Emergency Calling for Webex Calling](https://help.webex.com/en-us/article/av6oo3/Enhanced-Emergency-Calling-for-Webex-Calling), 'Location detection'. Checked 2026-09-25.
[^48]: Emergency calls go to RedSky only after the admin toggles on 'Route Emergency Calls to RedSky' for the location, which Cisco says to do after 933 test calls route correctly. Source: [Enhanced Emergency Calling for Webex Calling](https://help.webex.com/en-us/article/av6oo3/Enhanced-Emergency-Calling-for-Webex-Calling), 'Enable the E911 service for Webex Calling locations'. Checked 2026-09-25.
[^49]: Cisco's enhanced emergency calling article states that proper callback to the user relies on the ECBN associated with the user's location or phone number. Source: [Enhanced Emergency Calling for Webex Calling](https://help.webex.com/en-us/article/av6oo3/Enhanced-Emergency-Calling-for-Webex-Calling), Overview paragraph of 'Enhanced emergency calling for Webex Calling'. Checked 2026-09-25.
[^50]: Control Hub offers three ECBN choices for a calling entity: its own telephone number, the location default ECBN, or an assigned number from the entity's location. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), 'Options for ECBN configuration'. Checked 2026-09-25.
[^51]: Control Hub warns when a toll-free number is chosen as a location's main number because a toll-free number has no emergency service address. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), 'Configure a location number as the ECBN'. Checked 2026-09-25.
[^52]: A user's ECBN is set under Management > Users > (user) > Calling, via the Emergency Callback Number entry in the Numbers section. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), 'Configure a user's number as ECBN' steps 2-3. Checked 2026-09-25.
[^53]: Verizon's Webex Calling training tells admins to set up an emergency callback number for their locations to complete the enhanced emergency (RedSky) setup. Source: [Control Hub - Enhanced 911 (E911) Emergency Services (RedSky)](https://webexcallingtraining.verizon.com/control-hub-redsky-emergency-911-service/), 'Step 6: Enable the E911 service for Webex Calling locations'. Checked 2026-09-25.
[^54]: A virtual line's ECBN is set under Services > Calling > Virtual Lines > (virtual line) > Calling, via Emergency callback number in the Numbers section. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), 'Configure virtual lines as ECBN'. Checked 2026-09-25.
[^55]: Webex Calling accepts incoming calls carrying a Priority header marked emergency and, after a workspace places an emergency call, lifts that device's inbound call restriction for 60 minutes so the PSAP can call back. Source: [What's new in Webex Calling](https://help.webex.com/en-us/article/rdmb0/What's-new-in-Webex-Calling), March 26, 2025 entry on emergency callback for workspaces. Checked 2026-09-25.
[^56]: A workspace's ECBN is set under Management > Workspaces > (workspace) > Calling, via Emergency Callback Number in the Numbers section, with workspace number, location default ECBN or assigned number from the workspace's location as choices. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), 'Configure a workspace number as ECBN'. Checked 2026-09-25.
[^57]: Control Hub shows a warning when a workspace number or a virtual line is selected as the ECBN. Source: [Emergency Callback Number (ECBN) in Control Hub](https://help.webex.com/en-us/article/nzqvtyq/Emergency-Callback-Number-in-Cisco-Webex-Control-Hub), 'Configure a workspace number as ECBN'. Checked 2026-09-25.