What’s the Difference between SIP Trunking and PRI?

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When looking into telecoms and VoIP services, you will sooner or later come across the terms PRI and SIP trunking. But what on earth does it actually mean?

For most people, PRI and SIP trunking serves a similar purpose – after all, both technologies allow simultaneous calls over one line. However, when it comes to their features and capabilities, they are actually very different. Let’s take a closer look at Session Interface Protocol (SIP) and Primary Rate Interface trunking (PRI).


Essentially, what it all boils down to is choosing whether you want traditional telephony (which is what a PRI service is), or a voice over internet protocol (VoIP) delivered over SIP trunks. However, it’s imperative that you figure out their various capabilities – and identify which one will serve your business communication needs the best.

With cloud technology increasing in popularity, many companies are appreciating their cloud benefits, such as lower implementation and maintenance costs, and increased flexibility and productivity. For those very reasons, many businesses are switching over from conventional PRI phone systems to SIP solutions.

Despite the growing popularity of SIP and cloud communication tools, there are plenty of companies that still prefer their legacy phone systems. Others have adopted a hybrid approach, thereby taking full advantage of both technologies by blending legacy and IP phones into a single unified system.



What is a PRI phone service?

Let’s go back to basics for a second. A PRI phone service is a T-1 transmission solution, and the technology has been used as a business phone system for over four decades now. PRI supports voice communications, and it uses standard interface to deliver multiple lines of voice and information through actual physical lines made of copper. This essentially makes the network a part of your building’s physical infrastructure.

A standard PRI circuit is comprised of up to 23 voice channels, thereby supporting 23 simultaneous concurrent voice calls. It also has a data channel that supports call-related functionality, such as called ID.


The pros of PRI

A main advantage of PRI technology is that it doesn’t rely on bandwidth to support voice calls and deliver call-related data. In addition, this type of telecommunications system is capable of providing high-quality voice communication through dedicated line structure, whereas phone SIP technology will depend on the quality of the internet connection.


The cons of PRI

The biggest downside with PRI phone services is that it can be quite costly to implement and maintain. It can also require a quite hefty monthly phone service fee, which is a concern for any company looking for a cheap and reliable way of communicating with partners and customers.

Secondly, PRI is often complimented by long-term contracts. You will have to partner with traditional telecom companies to get your system up and running, so you might experience lengthy and costly contracts for long-distance calls. Scaling and modifications to infrastructure might also take long time to complete, which is not ideal for companies experiencing explosive growth.


Which type of business is PRI suited for?

PRI phone systems are ideal for companies that already have existing legacy PRI infrastructure in place. It’s also a reasonable option for businesses with limited access to fibre-optic internet connectivity or enough normal SIP trunk bandwidth to support SIP or IP-based phone communication solutions.

Many companies are now considering a hybrid telecoms solution. This is when companies retain their existing legacy PRI infrastructure while upgrading their communications capabilities through SIP technology.




What is SIP trunking?

Session interface protocol is designed to support VoIP communications. Essentially, it enables users to initiate calls between a VoIP line and another telephone number anywhere in the world. SIP technology is fully capable of transmitting voice calls in data form, as well as other types of multimedia communication.

SIP fully supports the transmission of unified communication, including text messages, data transfer, video conferences, and so on. With hosted or cloud-based systems, the service provider is generally responsible for not just the hardware and other equipment, but the transmission of voice data and other multimedia communications as well.

SIP technology is a good alternative to PRI phone services in that it removes the need for circuits and traditional telecom infrastructures, which effectively reduces the cost of maintenance and upgrades.


The pros of SIP

An obvious benefit of SIP trunking is the cost-effectiveness. Most vendors and service providers offer SIP trunking on a per-channel basis and on-demand. This means that customers will only pay for the capacity they need. More importantly, it’s significantly cheaper than traditional PRI services – with some customers reporting as much as 40% cost savings after a migration.

Some vendors also offer their services via the cloud as part of a unified communications solution, while also allowing for PRI phone lines integration for hybrid solutions.


The cons of SIP

The most obvious disadvantage of SIP trunking is that it requires a stable internet bandwidth in order to give you good quality calls. It’s often recommended to combine this with a business fibre internet, so that you can be sure that you get the quality and speed that you require.

Finally, if you’re using VoIP services, we recommend that you look into proper network security, such as firewalls, to minimize the risk of cyber-attacks. And remember that the quality of service and capabilities can vary quite a bit between vendors – this is why should always look into the service before signing a contract with someone. Find the 6 Best VoIP alternatives to Skype here.


Which type of business is SIP suited for?

SIP technology, such as VoIP, is ideal for companies that want to save money on business phone lines – and especially those who regularly make long-distance or international calls. For users relying on contact centre support, SIP is a cost-effective alternative to PRI.

VoIP can be a great help for businesses employing remote workers or with teams in various locations, as the cloud services will enable everyone to connect regardless of their location and time zone. This can help promote collaboration and improve productivity. It’s also a perfect option for smaller companies that can’t afford the PRI phone system and the communications infrastructure it requires.

Finally, VoIP services can easily be scaled up and down, which is great news for fast-scaling businesses.