SIP Trunking vs VoIP: What’s the Difference?

Call Center Operations | 3 minute read

SIP and VoIP are two acronyms often used by call center managers who sort of know what they mean, but also sort of… don’t.  Fair enough! Acronyms abound in the call center universe. It can be very tricky to navigate the intricacies of call center management and technology, and often, the language used just makes things more confusing. 

When it comes to VoIP and SIP, the terms are often used interchangeably, but they are different, and knowing these differences can add strength to your call center processes. We’re here to help! Let us explain the ins and outs of VoIP, SIP, and SIP trunking, and demonstrate how they can complement each other in your contact center environment.

Although we introduced this topic with the hundred dollar question (what’s the difference between SIP and VoIP?), a better question is:

Let’s start with some definitions.  

What is VoIP?

VoIP is an acronym for voice over internet protocol and, in some ways, that says it all. A VoIP call is an internet-powered voice call, and a popular alternative to the good old-fashioned landline phone call. 

What is SIP?

SIP, or session initiation protocol, is different but closely related to most VoIP applications. SIP is a network signalling protocol for setting up, maintaining, or ending communications sessions, which can include (but is not limited to) VoIP calls. SIP also facilitates other types of communications over the Internet, including multimedia messages like video calls, texts, and photo sharing.  

What about SIP trunking?

And where does the term “trunking” come in? In the before-Internet days, a trunk referred to a telephone line that served multiple customers, instead of one telephone line for one customer. Similarly, SIP trunking allows for shared access to a telecommunications network by multiple users. It’s common to think of a SIP trunk as a bundle of phone lines, but in fact, it’s really a single (virtual) connection with the capacity to host many simultaneous calls.  


What are the Differences? 

When considering VoIP and SIP trunking technology, there are a few key differences that illustrate how they work, and more importantly, how they work together: 

As we’ve mentioned, VoIP services offer only one type of communication: voice calls over the internet. SIP, on the other hand, is more versatile and can handle multiple types of sessions, including VoIP or voice calls, video calls, text messages, and more 

The vast majority of providers offer SIP to enable peer-to-peer VoIP calls and PSTN interconnection. SIP is the most popular protocol in the VoIP suite used by carriers today. Its ubiquity offers many advantages to its users, including easier implementation and reliable compatibility with many systems. 


Flexibility and convenience for your customer should be top priority to help boost your customer satisfaction scores. Fonolo Voice Call-Backs empower your customers by giving them the option to “press 1” for a call-back. Fonolo will then wait in queue for the customer and they will receive a call-back once it’s their turn.  

What are the Benefits of using VoIP and SIP Trunking Together? 

SIP and VoIP work great together and there are a number of reasons why they’re such a popular combination in the modern contact center.  

  1. Both systems provide telco cost savings to contact centers over traditional PSTN systems. 
  2. Customers can choose voice, video, or other channels with a SIP-enabled call center. 
  3. SIP-enabled VoIP calls scale with your business easily to accommodate growth. 
  4. You can reduce or eliminate hardware costs with the ability to deploy either system in a software-based environment. 
  5. They easily integrate with your other systems and vendors.
Fonolo Resource cover image

The Ultimate Call-Back Tactical Handbook

Download Now

The Ultimate Call-Back Tactical Handbook

The Ultimate Call Back Handbook
Download Now
Fonolo Resource cover image

The Ultimate Call-Back Tactical Handbook

Download Now

See Fonolo in Action

Select the type of demo you'd like.

By continuing to browse our website, you agree to the use of cookies for providing our services, marketing purposes, and analytics. To understand more about how we use cookies and ensure the safety of your data, please refer to our Privacy Policy.

Accept and Close