SIP trunking vs PRI

SIP Trunking vs PRI: What Are The Major Differences?

For an industry based on communications, telecoms are chock full of acronyms.

Many businesses are falling behind on technology. Some are struggling to stay technology relevant. Often, confusion is a barrier to enterprises who want to upgrade their IT.

That’s why we’ve put together this guide. When it comes to SIP trunking vs PRI, you’ll need to get a good understanding of them both before you can decide which is right for your business.

Read on for our breakdown!

What is SIP?

SIP is a telecommunications protocol and a form of VOIP. It stands for Session Initiated Protocol.

SIP trunking essentially turns your cloud network into a telephony system. Unlike a traditional phone system, SIP isn’t carried on a regular phone network and doesn’t use a traditional phone company. The data from a SIP connection is carried online.

As SIP trunks are virtual, they don’t require the hardware involved in a PRI connection. SIP providers take the place of traditional phone companies for SIP connections. They provide virtual phone lines for enterprise use.

What’s PRI?

PRI stands for Primary Rate Interface. It’s a telecommunications technology based on physical hardware and the ISDN, rather than modern data connections.

PRI is carried on T1 and E1 trunk lines between the telecom provider’s service station and the customer’s locations. PRI represents an older branch of telecoms technology, but it still has a few advantages despite its age.

The Head to Head

SIP and PRI are two different methods of achieving the same result, so they both have their pros and cons when we’re talking about SIP trunking vs PRI.

Businesses will want to carefully look at each to decide which is right for them. There’s no one-size-fits-all solution because much will depend on the nature of the enterprise.

PRI: The Pros & Cons


“Quality” best describes the pros of PRI.

Unlike SIP, PRI doesn’t ride on the network. That means network problems like packet drops and bad connects won’t impact PRI call quality.

How important that is to you depends on the nature of your company. It’s only likely to become an issue if line quality is paramount to your communications.

However, it does mean that companies with poor internet access might find it better to invest in a PRI network.

Another advantage of not using network infrastructure is security. PRI is carried by the phone network, so PRI doesn’t require the kind of firewall technology needed to ensure the security of SIP.


Scalability is poor with PRI. Upgrading often needs costly infrastructure which can take weeks to be put in place.

It may also cause disruption during installation. This might not be a concern for a static company, but a growing one is likely to spend a lot of time and money keeping PRI up-to-date with the needs of the business.

SIP: The Pros and Cons


SIP’s major selling point is its simplicity.

If a business is already networked, then it won’t take much to get SIP up and running. The simplicity of installation also gives it a lot of flexibility. That’s great news for a fast-growing company that may be shifting teams or hiring frequently.


Some businesses don’t have the network infrastructure for SIP trunking. In this case, they would have to upgrade before going with SIP.

The reliability and pricing of SIP providers can vary greatly. It t can take some time to shop around and find the best deal for your business. Of course, this is a pro, too. It means there’s a possibility of getting a bargain for the service!

Competition between SIP providers also helps control the prices.

Which is Right for Me?

When it comes to choosing between SIP trunking vs PRI, you’ll want to take a number of factors into account.

Do You Have Multiple Locations?

SIP is a stronger option for a company working out of multiple locations.

It allows for much greater redundancy, such as rerouting calls from one location to another. You can pre-program these redundancies, too. That means they can form a vital part of your business continuity plan.

Do You Need High-Quality Calls?

For most businesses, serviceable line quality is enough. That means SIP is usually good enough to meet the needs of most businesses.

If line quality is important to your business, you might want to invest in PRI. The dedicated lines and bandwidth of PRI mean higher quality lines and less dropped data. This is the solution for a company who can’t afford miscommunication in calls.

Are You Looking for Cost Savings?

Due to its low set-up costs and the ease of making changes at a later date, SIP tends to be the more budget-conscious option.

In the case of PRI, there are monthly costs associated with the infrastructure that can quickly add up. Additional service costs can also apply if under heavy usage.

Do You Have Good Internet Infrastructure?

While SIP can be simple to set up, it depends heavily on your computer network.

Take into account the load your internet connection will be under when it reaches peak business times. If you aren’t confident your network can handle SIP, then PRI might be the better option.

If you’re a high-bandwidth business, such as a call center, then PRI could help you manage your calls. Unlike SIP, PRI has a set amount of bandwidth for each call, so call quality is unaffected by service usage.

Are You Growing Quickly?

SIP lends itself much better to a fast-growing business. It can be easily upgraded and moved around, making it cost-efficient for a business looking to make many rapid changes.

Meanwhile, PRI is an expensive solution when it comes to rapid expansion. New circuits have to be individually purchased. They can also take weeks to set up.

PRI also requires new hardware, so the disruption of set-up can have a significant knock-on effect for your business.

SIP Trunking vs PRI

We can’t tell you exactly which technology will fit your business. But by keeping the above in mind, you should be able to make the decision when it comes to SIP trunking vs PRI.

Got any questions or need some advice? Reach out and talk to us! We’re always happy to help. And, be sure to follow our blog for more telecoms advice and guides!