Emergency Calls

  • Updated on December 6, 2022

In critical situations, having the ability to make emergency calls to ask for help is a must for any telephony system, whether it’s public telephony system such as a GSM network or PSTN network, or the private local telephony system managed by the PBX on-premises.

Grandstream’s enterprise-grade IP-PBX provides users with the ability to manage such types of calls to help users deal with critical situations and make emergency calls for help. These calls need to have higher priority than regular calls, categorized depending on the emergency service called and the ongoing situation as well as the possibility to notify related personal about the situation (guards, first aid … etc.).

UCM6xxx series provide the administrator with all tools necessary to configure and adapt the PBX to such situations, making it possible for users to easily press buttons or dial codes/numbers to make emergency calls.

We will cover in this guide all the needed steps to configure emergency calls on the UCM IP-PBX series.

UCM6XXX series include UCM620x series, UCM630x series, UCM630xA series, and UCM6510.

Scenario Overview

To illustrate the functionality of emergency calls on the UCM6xxx series, we will be using the following scenario where company ABC has already deployed a UCM6510 as their main PBX system along with GXP21XX phones for users.

Company ABC uses a SIP trunk as their main exit point and two PSTN lines as backup in case they lose internet connection.

Users are allowed to make external calls depending on the established routing policy (permissions, privileges, PIN codes …etc) while respecting the following requirements:

  • All users should be able to dial emergency number at any time without any restrictions.
  • The system admin would be receiving email alert notification about the made emergency calls.
  • Users with extension 2001, 2002 and 2003 should receive vocal notification when an emergency call has been initiated.
  • Emergency calls should go over the PSTN lines 1 and 2.
  • If there is an ongoing call on the PSTN line, the system should drop it when there is an emergency situation to connect the person who dialed the number with the emergency service.
  • Users are only allowed to dial following emergency numbers: 911, 811 and 711 with the first one having the highest priority and the last the least.
Scenario Overview

Configuration Steps

In the following sections, we will be covering all necessary steps to configure the system to fulfill the requirements discussed in the scenario overview section. First, we need to set up the prompts that we will be played to the users when someone dials an emergency number.


If no custom prompt is configured, the PBX will play the default one.

Customize Notification Prompts

In order to create a custom prompt that will be used as a notification when an emergency call is initiated, users need to log to the web administration page of the UCM under “PBX Settings 🡪 Voice Prompt 🡪 Custom Prompt” then they have two choices:

  1. Upload a pre-recorded prompt by pressing the “Upload” button but the file should respect the following specs:
  • PCM encoded.
  • 16 bits.
  • 8000Hz mono.
  • In .mp3 or .wav format; or raw/ulaw/alaw/gsm file with .ulaw or .alaw suffix.
  • File size under 5MB.

If uploading a compressed file, the file must have .tar/.tgz/.tar.gz suffix, name must contain only letters, numbers or special characters -_. and the file size must be less than 30MB

  1. Record a new custom prompt by clicking on the “Record” button then select the recording station on which you want to record.
Recording Custom Prompt

Now that the custom prompt is ready, we will be using it as a vocal notification to some users, but what about the system admin who usually received notifications via email?

For that, we will need to set up alert events and enable email notification when emergency calls occur to notify the administrator(s) about the situation.

Email Notification

To configure and enable email notification there are basically two easy steps.

Step 1: Configure Email Settings on the PBX.


Please refer to the following guide to set up the email settings for UCM63XX. https://documentation.grandstream.com/knowledge-base/ucm630x-email-settings-guide-gmail-as-smtp-server


  • Users have the ability also to customize the emails that will be sent by the UCM under the tab “Email Template” for multiple tasks (Fax Sending, CDR, Alert Events …etc).
  • Users can check the email send logs under “Email Send Log” tab to view the history of the emails that where sent by the UCM.

Step 2: Enable Alert notification for Emergency calls.

Next, we need to enable the alert event for the emergency calls as well as email notification or this type of event. First, make sure to configure the alert contacts under the menu “Maintenance 🡪 System Events 🡪 Alert Contact” as shown below.

Alert Contacts Configuration

After this, users need to enable the alert notification for emergency calls under the « Alert Events List » tab.

Activate Alert Events

The UCM will send its device name in the Alert Event email.

Adding Emergency Numbers

In this section, we provide the steps to configure the different emergency numbers that users in company ABD are allowed to dial and set the priority for each one as described in the requirements sections.

We assume that the admin has already configured the trunks and inbound/outbound routing policy to send calls to the external networks (PSTN and ITSP).

To configure emergency numbers, users need to follow the below steps:

  1. Navigate on the web GUI under “Call Features 🡪 Emergency Calls”.
  2. Click on A close up of a sign

Description generated with high confidence to add a new emergency number.
  3. Configure the required fields “Name, Emergency Number and Trunk(s) to be used to reach the number”.
  4. Set the Emergency level for the number (ex: Significantly Urgent was used for 911 on this case)
  5. Save and apply the configuration.
Emergency Number Configuration

Users could follow the same model to add the rest of the numbers and assign each one the required level.

The table below gives more descriptions of the configuration parameters when creating emergency numbers.


Configure the name of the emergency call.

For example, “emergency911″,”emergency211” and etc.

Emergency Number

Config the emergency service number. For example,”911″,”211″ and etc.

Emergency Level

Select the emergency level of the number. Level “3” means the most urgent.

Disable Hunt on Busy

If this option is not enabled, when the lines of trunks which the coming emergency call routes by are completely occupied, the line-grabbing function will automatically cut off a line from all busy lines so that the coming emergency call can seize it for dialing out.

Note: This option is not enabled by default.

Custom Prompt

This option sets a custom prompt to be used as an announcement to the person receiving an emergency call. The file can be uploaded from the page “Custom Prompt”. Click “Prompt” to add an additional record.

Use Trunks

Select the trunks for the emergency call. Select one trunk at least and select five trunks at most.

Members Notified

Select the members who will be notified when an emergency call occurs.


Specify the number of digits that will be stripped from the beginning of the dialed number before the call is placed via the selected trunk.


Specify the digits to be prepended before the call is placed via the trunk. Those digits will be prepended after the dialing number is stripped.

Auto Record

If enabled, the calls using this extension or trunk will be automatically recorded, default is disabled Note: Emergency recording will be also available under Emergency Recording Tab.

Send Recording File

If Enabled the recordings will be sent to the configured Email address(es)

Email Address

Used to specify the Email address(es) for Emergency calls recordings.

Table 1: Emergency Numbers Parameters

Below is a screenshot of the configured numbers following the company’s ABC requirements.

911 Emergency Sample

Emergency Recordings

The UCM6200/UCM6510/UCM6300 allows users to record the Emergency calls and retrieve the recording from Web GUI→Call Features→Emergency Calls→Emergency Recordings.

To record the Emergency call, users need to enable “auto record” from the Emergency calls configuration, save the setting and apply the change. When the Emergency call starts, the call will be automatically recorded in .wav format. The recording files will be listed as below once available. Users could click on to download the recording or click on to delete the recording. Users could also download all recording files by clicking on “Download All”, or delete multiple recording files at once by clicking on “Delete” after selecting the recording files.

Emergency Recording

Emergency Location Mapping

Emergency Location Mapping allows the user to associate specific locations with specific subnets. This helps with tracking down from where the call was initiated. This can be done through the help of Emergency Line Identification Number (ELIN). Providing this information, the Public Safety Answering Point can pinpoint the exact location where the call had been initiated. This feature can be found under Call Features → Emergency Calls → Emergency Location Mapping.

Create New Emergency Location Mapping
  • ELIN: The emergency location identification number registered with the E911 provider. This number will be sent out as the emergency call’s CID number.
  • Subnet: The network subnet that the ELIN will be associated with. The ELIN that is sent to E911 providers is based on the subnet that a calling endpoint is registered from. Example: “xxx.xxx.xxx.xxx/24” or “xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx/64”.
  • Location: Location associated with the configured subnet. This is used for the UCM administrator’s reference.
  • Geolocation Routing: Toggles whether to include the Geolocation header in the emergency call SIP INVITE message. The Location field value will be used as the Geolocation header value.
Important Note

Please note that ELIN Mapping is supported only on peer trunks. It would not apply on register trunks.

Below is an example of a capture trace of network traffic that contains the Geolocation header.

Network Traffic Capture Trace

Use Case Sample

During working hours, both PSTN lines were occupied with normal calls and suddenly an urgency situation occurred and the user with extension 2018 dialed 911.

Active Calls

Once the user dialed the 911 emergency call, the UCM will drop one of the calls in order to give priority to the emergency call as well as sending notification to the other users as seen on the screenshot below

Active Calls 2

The call which was dropped is the one occupying line1 since it’s the line with the highest priority. This behavior is mainly because we had the option “Disable Hunt on Busy” deactivated, if activated, then the UCM will not hunt on busy lines to allow emergency calls to go through.

After the call has been initiated we can see also that UCM is sending notification calls to the selected users which could be personal for first aid at the company, and they will hear the custom prompt configured on the 911 emergency number, if non-specified then the default prompt will be played.

The system admin did receive on the fly the following Email notification.

Emergency Call Alert Event Email

Also, events notifications can be seen on the UCM’s web UI under Maintenance 🡪 System Events 

System Events (Emergency Calls)

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