Reach Out and Connect When Emergencies Arise
There are many different aspects an organization should consider when deploying a new phone system, not only when it is based on Microsoft Teams.
Emergency calling is one of them, and it must be reliable at all times, especially in situations requiring medical assistance where quick help is crucial. Emergencies can occur in the office, on the floor, or in production areas. In such cases, it’s vital that people can use the phone system to summon help immediately.
A company must also comply with the regulations for emergency calls. These can be legal requirements (depending on local legislation), but also requirements relating to occupational health and safety or plant safety. More information can be found here as an example for the US and Germany:
In terms of hybrid work, emergency calling poses some special challenges for the PBX team. A user can work at the company on campus or from home and use a softphone such as Teams to dial the emergency services. Regardless of the location, the emergency call should always go to the nearest emergency call center. And therein lies the challenge. How can the softphone know whether the user is in the home office or at work and route the call accordingly?
For all these reasons, emergency calling needs some attention when planning a phone system migration to a softphone solution. Let’s explore how Teams copes with emergency numbers.
Routing Emergency Calls
In most countries, 112 or 911 are established emergency numbers. Telephone providers route calls to the speed dial number to the relevant emergency call center. It is therefore important for the providers to know the current location for the emergency call.
Usually, the provider recognizes the current location of the user based on the source phone number and its registered street address. In some countries, the street address is not enough, and detailed information is required. For example, depending on the size of the building, it may be required by law to include information about the floor or office. This is the case in some US states.
The street address, or rather the user’s current location, is crucial for emergency calls from a landline. In the case of an emergency call from a cell phone, geodata is the usual method to determine call location.
Teams Emergency Calls
Microsoft offers different ways to connect PSTN to Teams: Calling Plans by Microsoft, Operator Connect or Teams Phone Mobile from a certified carrier, and Teams Direct Routing.
In general, all types of PSTN connectivity support emergency calling by default and emergency calling works out of the box.
All PSTN Types share a common aspect: the phone number is registered to a specific street address. And this registered address is used by the provider to find the nearest emergency call center.
Whether detailed location information is required can be agreed with the PSTN provider and the company’s legal team. For location determination, Teams has the option of linking network parameters such as Switch Ports, MAC addresses of switches, WiFi BSSIDs, or subnets with street addresses in the Teams Admin Center. When Teams starts up, the client attempts to determine its location based on the current network and can transmit the extended location data in the event of an emergency call.
Teams client’s go through a structured process to determine the location. First, it tries to determine the location via the WiFi BSSID, then via the switch port or the MAC address of the switch. If there is no match, the Teams client tries to determine the location using the current IP subnet. Further details can be found in the documentation.
In addition to location determination, Teams performs other functions, such as:
- Displaying the initiation of an emergency call bin the Teams calling window (supported only with Teams Direct Routing)
- Informing the organization about an ongoing emergency call via Teams chat or conf-in to an external phone number
- Mapping different emergency numbers to a single number
- Detecting the current user’s location based on network or GPS (if the device supports it) and including the location address in SIP when initiating an emergency call
- Dynamic call routing based on the user’s location
Configure Emergency Calling Policy in Teams Admin Center
The Emergency Calling Policy is in the TAC’s Voice section. The policy is used to display a disclaimer in the Teams call app, allow external address lookup, and configure a mechanism informing other Teams users about an ongoing emergency call.
The External Address lookup is dedicated for Work from Home scenarios. If the Teams Client doesn’t detect the current user location based on network information, the user can manually enter the current location’s address.
Teams provides a wizard with auto suggestions for entering the address or a mask to enter the address manually.
The policy also supports functionality to inform specific Teams users, via Teams Chat or start a conference and dial a PSTN number, when a Teams user dials a defined emergency dial string.
The Emergency Calling Policy can be assigned to individual users or to everyone within a network site. If a policy is assigned to a user and the user is connected to a network site with a different Emergency Calling Policy, the network-related policy takes precedence.
Configure Emergency Call Routing Policy in Teams Admin Center
The Emergency Call Routing policy is used for dynamic call routing and is only applied when using Teams Direct Routing.
The policy includes an option to map different emergency numbers to a single dial string and identify emergency calls based on these strings. The Teams administrator must assign a PSTN usage record, otherwise, the policy cannot be saved (Figure 1)
If there is an Emergency Call Routing policy added to the tenant and assigned to a user or network location, Teams displays a message in the call window that an emergency number has been dialed (Figure 2).
Like the Emergency Calling Policy, a network policy takes precedence over a user-assigned policy.
Points to Consider
Like any technology, some important points should be reviewed before deployment. Here’s what you need to consider for emergency calling:
- If the administrator updates or adds new information in Network & Locations or Network Topology, it takes up to four hours for the backend sync, and the new information is fully propagated.
- The auto-detection mechanism of the user location based on the office’s subnets only works if the public WAN IP address is set as a Trusted IP address in TAC. For the other mechanisms like WIFI BSSID, Switch Port, or Switch Mac address, it is not required to set up the WAN IP addresses.
- The mechanisms described to detect the user’s location do not work with the Teams Web App. Other clients like the Windows or macOS Desktop Client, Android/iOS Mobile App, Teams Phone App, MTR on Windows, or MTR on Android support automatic location detection.
- When a user performs an emergency call and the emergency location has an ELIN configured, the emergency center can call back the user for the next hours on the ELIN number. During this period the user does not receive calls on his personal DDI to prevent any missed calls from the emergency center
- When everything is in place and the Teams Administrator configured emergency addresses and network locations correctly, it might be that the Teams client does not detect the location, and users must enter the address manually.
- In that case, the Teams Administrator can analyze the Teams client support log. The generated ZIP file includes a folder structure, each folder has a log file named calling-debug.txt. This file includes assigned emergency policies and basic network and location information. In the example shown in Figure 3, the public IP doesn’t match one of the Trusted IPs from TAC:
Summary
When I help my customers migrate their classic PBX to the Teams Phone System, emergency calling is one of the main topics.
The first discussion is often the “Work from Home” scenario, and the second is usually that a user must be able to make an emergency call at any time, even if the PC (and therefore the Teams Client) is shut down.
With Emergency Calling, features that work from anywhere can be addressed, but admins need to spend time on it during and after deployment. Each new network site, each new WAN IP address, and any change to the existing network topology must be approved by the Teams administrator and checked if it requires a change in the TAC’s Locations section.
I recommend that administrators consider whether emergency calling is required when they create and manage Teams locations.
The conditions under which emergency calls are made at a location should always be agreed with site managers. If the Teams administrator is not sure whether location information must be transmitted during an emergency call, they should ask the PSTN carrier.
Last but not least: the test plan after a changeover should always include an emergency call to ensure that everything continues to work after these changes.
