Emergency Calling

What? Why? How? and Testing with XGP

By Kusal Fernando

What is Emergency Calling?

Emergency calling allows a mobile device to make a call to emergency services (e.g., 112, 911,) even without a valid SIM card, or when the SIM is not registered to the network. This is a regulatory requirement in most countries and is supported by all GSM/UMTS/LTE networks. 

Why Emergency Calling is Important?

Emergency calling systems are designed to be robust and universally accessible, still there have been critical incidents where these systems have failed, leading to severe consequences.

For an instance, during a major outage in Australia, hundreds of emergency calls to Triple Zero (000) did not go through, reportedly resulting in multiple fatalities. Tragically, this led to multiple deaths, as individuals in life-threatening situations were unable to connect to emergency services. 

Why is Testing Crucial?

One of the very common failures is technical faults during a routine upgrade, which can go undetected due to insufficient testing and lack of a proper failover system. Although regular calls remained unaffected, the emergency call infrastructure is separately managed and regulated which can be compromised, violating critical obligations under the Telecommunications (Emergency Call Service) Determination 2019. This is exactly what happened during the recent incident occurred in Australia.  

How does Emergency Calling Work? 

As mentioned above, emergency calling is designed to work without/with a (U)SIM. There are two kinds of ECC (Emergency Call Code) numbers: ECC numbers without (U)SIM and ECC numbers with (U)SIM. The default ECC numbers without (U)SIM are 911, 112, 00, 08, 110, 999, 118 and 119. The default ECC number with (U)SIM is 911 and 112. 

Without a (U)SIM or with an Invalid (U)SIM 


• The device scans for any available network, regardless of operator. 

• It attaches to the strongest cell tower that allows emergency calls. 

• The call is flagged as emergency-only, and the network permits it even though the device is not authenticated. 

With a (U)SIM


• The device uses its own network or a roaming partner to initiate the emergency call. 

• The call is routed through the standard call flow but flagged as emergency-only.

• The network prioritizes this call and routes it to the Public Safety Answering Point (PSAP). 

XGP 2.0 (Front View and Rear Views) - 5X RF Radios and 30X SIM slots

Testing with XGP

XGP is a powerful, integrated platform combining software intelligence with built-in RF GSM radios, designed to automate and simplify telecom testing. XGP’s embedded GSM/UMTS/LTE/5G radios allow direct interaction with live networks. 

Full Automation

Automated test execution eliminates the need for manual dialing, logging, and monitoring. And tests can be scheduled based on requirements. Such as, 

DCS Octet Structure:


• Multiple times daily as sanity checks 

• After network upgrades or firmware changes 

• On-demand, based on client-defined triggers 

For an instant, let’s take a test case of “Emergency Call Testing - with (U)SIM” with XGP  

Create a new execution with a configurable RCC to be tested. 

Image: Creation of a Test Definition with Execution Variables

Test Script with Test Steps


• Read the signal strength and IMSI of the (U)SIM 

• Read the existing configuration of RCCs in the RF module and add if RCC is not already configured.   

• Then make the call and hang up after few seconds.  

• Note:

In this example, the actual dialing step of the emergency call was intentionally skipped, as executing live calls to a PSAP (Public Safety Answering Point) in a production environment is not advisable without prior coordination 

Image: Test Script with Test Steps

Testing on Production Environment 

Emergency calls are designed to route through any available network operator, regardless of SIM status. Therefore, to test emergency calling in a production setup, the following precautions and configurations are recommended:

Controlled RF Environment (Faraday Cage) 


Deploy the device inside a Faraday cage or RF-shielded enclosure that allows selective signal to be injected. This setup ensures the device only receives signals from a specific operator, enabling controlled testing without interference from other networks.

Operator & PSAP Coordination 


The mobile network operator or the associated PSAP must provide access to a test Routing Control Center (RCC) or a designated emergency call test endpoint. This allows emergency call flows to be validated without reaching live emergency dispatch systems. 

The Business Impact

Emergency calling isn’t just a regulatory checkbox but it’s a lifesaving capability. From a business and operational standpoint, ensuring its reliability is essential for: 


• Public Safety Assurance: Guaranteeing that users can reach emergency services under all conditions. 

• Regulatory Compliance: Meeting national and international mandates for emergency accessibility. 

• Brand Trust: Avoiding reputational damage from failed emergency calls during outages or disasters. 

The Engineering Challenge 

For engineers and QA teams, emergency call testing often raises questions like:


  • Manually creating PDUs for different encoding scenarios? 

  • Testing only GSM 7-bit and hoping for the best? 

  • Struggling with international character set validation? 

  • Facing issues with binary message delivery? 

Manual testing is slow, error-prone, and hard to scale. The question isn’t if you should automate, it’s how fast you can deploy a solution that handles the testing for you.

What challenges are you facing with emergency call testing? Have you encountered failures in production that could’ve been caught with better automation? 

I'd love to hear about the SMS testing challenges you're facing and discuss how modern automation approaches can help. 

Let’s discuss how XGP can help you validate emergency calling with confidence and prepare your network for the future of public safety communications. 

Want to see XGP's emergency call testing capabilities in action?

Visit XGP | End to End Test Automation for Mobile Operators or contact us directly for a technical demo.