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PRI vs. SIP trunks: which is best for business communications?


April 26, 2019


December 8, 2021


PRI vs SIP Trunks.

When it comes to business communications, who’s the winner?

Today’s enterprises are outgrowing their legacy communications in high numbers due to their growing need for more agile, scalable solutions that help them reduce their operational overheads while also delivering improved customer experience and engagement.

If you are one of those businesses, you need communications that can easily scale without sacrificing reliability, network stability, or compliance.

How do SIP trunks rank when compared to PRI in these areas?

The SIP trunk market has exploded in recent years and shows no signs of slowing down. Independent research shows that up to 80% of organizations in the US and Western Europe are already testing SIP trunking as an alternative to traditional ISDN PRI voice communications.

Yet, despite how quickly companies are adopting SIP trunks, there is still a large number of businesses relying on PRI as their primary form of voice communication.

What could possibly be so compelling that so many people are reluctant to part ways with an outdated communications process?

The PRI advantage

Without getting overly technical, PRI phone lines are an enhanced version of standard copper phone lines. They were designed to meet the complex needs of businesses, with both analog and digital data transmitted across the PRI to provide clear voice communications.

Companies who upgrade from traditional copper phone lines to PRI notice an immediate improvement in call clarity and quality. An excellent perk if you are trying to create a great first impression with your customers.

PRI lines can scale, but not without cost. So, if you operate a phone system that is regularly congested, it is easy to add additional lines as needed.

On the other hand, if you use several PRI lines, you might even choose to route call traffic over multiple lines so that no single line ever reaches max utilization.

It’s not difficult to install PRI lines either. This is crucial to organizations that might not be able to sacrifice operational time to install or maintain a phone system.

PRI uses pre-existing copper lines, meaning you will only really need to purchase the equipment and have it installed at each physical office location to be up and running.

The SIP trunk advantage

SIP trunk technology is fundamentally different from every type of legacy telephony out there. It harnesses enterprise-grade to make and receive voice data networks – from private backbones through to the public internet – to deliver call traffic between organizations and the PSTN – the global aggregate of the world’s public telephone networks.

Through a SIP gateway, voice traffic delivered over SIP trunks can easily be delivered to and from the PSTN, meaning that businesses can make and receive calls indistinguishable from those made with an incumbent carrier.

This has the added advantage of allowing for calls to be made in one country and presented locally, but routed to a remote location – so companies can establish a local presence in multiple markets from a single centralized location – perfect for use cases such as contact centers and conferences.

As an added benefit, when compared to PRI lines, SIP trunk users can expect to see anywhere from 25% to 50% savings on their monthly phone bills.

Another problem is the PRI’s issues with scaling. They can scale, but not nearly as easily as SIP.

To scale a PRI  line, you need to do so in bundles. For example, if one PRI line can support 23 concurrent lines and your business requires 25 lines, you would be stuck with the decision of whether to stick with one line (and sacrifice call quality and customer satisfaction) or pay for two PRI lines.

SIP trunks aren’t nearly as restrictive, all you need to do is increase bandwidth and you can add as many channels as your business requires. You can also easily remove unused channels which can result in impressive cost savings.

PRI lines are isolated systems and incapable of sharing data. SIP trunks, on the other hand, can operate interchangeably with ERM and CRM solutions and many other enterprise systems.

The PRI vs SIP trunks winner: SIP trunks

SIP trunk providers are continuously improving, seeking out new innovations, and adding new tools to improve and enhance the way our customers communicate and collaborate – tools that are often difficult (and even impossible) to implement over PRI lines.