911 Trunks with NG911: Fixing the Emergency Phone Call Overload - NGA

Posted in NGA911 on Oct 19, 2022

911 trunks are a vital part of our nation's emergency response infrastructure. Public Safety Answering Points (PSAPs) handle millions of calls each year, and 911 trunks are essential to ensuring that every one of those calls is answered. But not every call that reaches dispatchers is an emergency. Unfortunately, 911 call centers are overloaded due to communication technology advancements. 

The influx of non-emergency phone calls is putting a strain on the current 911 system, leaving actual emergencies unanswered by outdated infrastructures already struggling to keep up. Thankfully, there is a solution: NextGen 911.

In this blog from our NG911 providers and experts at NGA, we'll discuss 911 trunks and how they're being used in the NG911 system to clear up the congestion of emergency phone calls in call centers across the country. 

Table of Contents:

  1. What are 911 Trunks Exactly?
  2. How Do 911 Trunks Work?
  3. NG911: The Next Generation of 911 Response 
  4. Understanding How Next Generation 911 Works
  5. What are NG911-Capable Trunks?
  6. The Importance of Next Generation-Capable 911 Trunks 
  7. Conclusion 

What are 911 Trunks Exactly?

911 trunks are essentially extra phone lines dedicated to incoming 911 calls. They are specialized phone lines designed to connect an emergency call center (ECC) or Public Safety Answering Point (PSAP) to the phone network being used by the 911 caller. 

How Do 911 Trunks Work?

Traditionally, when a caller dials 911, their call is routed through a trunk line to a dispatcher. Trunk lines help reduce the time it takes for a dispatcher to answer a call, which is especially important in high-traffic areas where wait times can be upwards of 10 minutes or more. 

911 trunks are typically used by large organizations such as hospitals or universities. They may also be used by small businesses or private residences that receive a high volume of calls. 

When an emergency call comes in on a 911 trunk, it's to be given priority over other non-emergency calls, ensuring the call goes through. However, with outdated telecommunication systems and technology, emergency call centers cannot stay ahead of 911 caller congestion. 

NG911: The Next Generation of 911 Response 

NG911, or Next Generation 911, is an entirely digital infrastructure. The system was developed to be more scalable and efficient, routing callers to the appropriate PSAP based on location. 

The NG911 system also supports multi-media messaging and data sharing so that dispatchers have all the information they need at their fingertips. 

Understanding How Next Generation 911 Works

NG911 works by using Internet Protocol (IP) networks to route calls. This means that instead of using traditional telephone lines, the NG911 infrastructure uses the internet to connect callers with dispatchers. 

Because Next Generation 911 runs on entirely interconnected, cloud-based networks, callers can send text messages, photos, and videos to 911 dispatchers in real-time. This multi-media data sharing can be helpful in situations where it is not safe or possible to make a call, such as during a home invasion or active shooter situation. 

Next Generation 911 also allows dispatchers to pinpoint the caller's exact location by using Geographic Information System (GIS) technology. NG911 is currently being implemented in many states across the country and is the new standard for emergency response in America.

What are NG911 Capable Trunks? 

For a trunk to be NG911 capable, it must be able to support multi-media service interactions between 9-1-1 call takers and first responders. This means that the trunk must be able to handle things like text messages, photos, and videos in addition to traditional voice calls. 

The Emergency Services IP Networks, or ESINets, on which the Next Generation 911 infrastructure runs, rely on a foundation of Session Initiation Protocol (SIP) trunks. For a 911 trunk to be NG911 capable, the call center's phone system must be upgraded to a Voice over IP (VoIP) system that supports SIP. 

The Importance of Next Generation-Capable 911 Trunks 

Traditional emergency response systems rely on Centralized Automatic Message Accounting (CAMA) trunks. Outdated systems use Automatic Number Identification (ANI) to identify the location of the 911 caller, and a direct relationship between the dispatcher and the local 911 office exists for using these single-purpose trunks. This CAMA trunk system worked well for 911 systems in the past designed for landlines but is not efficient enough to meet the immediate needs of our digital society. 

Because every second counts in an emergency, the multi-media handling capabilities of NG911-capable trunks mean dispatchers can receive vital information from people at the scene of an incident. This data can help first responders make informed decisions and provide them with a better understanding of what they're dealing with. 

In addition, NG911-capable trunks can help reduce congestion on the 911 phone lines. With more people sending text messages and videos instead of making voice calls, call takers can free up capacity to handle other emergency calls. 


NG911 represents a significant shift from the current 911 system in the United States. The move to IP-based 911 trunks will provide increased reliability, capacity, and flexibility for PSAPs. 

In addition, NG911 will enable innovative features such as text-to-911, location services, and multi-media data sharing. These solutions will benefit public safety professionals and the general public by providing a more efficient and effective emergency response system.

Would you like to learn more about 911 trunks like NGA's 911 NG Trunk? 

Connect with our NG911 experts and providers at NGA to get started today!