By upgrading your communication phone systems and associated software, you will help your business stay relevant while providing a better service to your customers.

Two of the most commonly-used communication protocols include VoIP delivered over SIP or a PRI phone system.

Both PRI and SIP will serve the same purpose for your business, allowing you to upgrade to a more efficient and easy to manage business phone system. However, how they go about achieving this service is a bit different.

When it comes to choosing between SIP trunking vs PRI, you should be well-educated on both so that you can make the best decision for your business.

Learn how SIP and PRI stack up against each other

What is SIP?

An existing VoIP connection uses the Session Initiated Protocol (SIP). Mostly, it’s a set of technical standards that support VoIP calls and the transmission of data over a VoIP connection.

SIP trunking will transforms your entire cloud network into a telephone system. Every call will take place over the network, instead of traditional telephone lines. You do not need any extra hardware (SIP Trunking Equipment’s) except VoIP compatible phone system.

The most significant difference between SIP and PRI is that SIP is a telephony networking protocol, while PRI is a telephone technology in itself.


SIP trunks shine in their simplicity. If your business is already set up with a network phone solution, like VoIP, then setup can be relatively quick and hassle-free. You also can scale your SIP phone network quickly as your phone demands shift.


Quality offered between SIP providers can vary greatly. Do your research and always choose a SIP providers that has a track record of success.

What is PRI?

Primary Rate Interface (PRI) has been used for voice communications for over 40 years now. It’s a telecommunications technology that relies upon physical hardware. For decades it’s been the industry standard for business telephony until cloud providers and voice over network technology came into being.

It uses physical hardware and an Integrated Services Digital Network (ISDN) to deliver multiple lines of voice and data, all through a single physical circuit. These PRI circuits will provide support for up to 23 voice channels, 23 concurrent calls, and a channel for data.


One area where PRI shines is in call quality. Since it does not rely upon a network, you do not have to deal with network issues, bad connection, or packet drops. Usually, the quality of most business network connections will not cause these issues to arise, but for some businesses, it can be an issue. If you have poor internet access in your area, then using PRI might be your only option. PRI can also be more secure since it does not rely upon a network connection. By using, phone lines you avoid having to do things like setup network firewalls.


If you need more flexibility from your business phone solution, then you might run into issues. Since PRI relies upon physical infrastructure upgrades can be costly. If you are growing fast and need to upgrade your system, then this could lead to network outages while this takes place.

Bird's eye view of critical differences between SIP trunk and PRI.

Parameters SIP (Session Initiated Protocol) PRI (Primary Rate Interface)
What are SIP and PRI? SIP trunking is a protocol used to stream media service over VoIP PRI is a form of traditional phone lines to carry voice, data and video
Which business does it suit best? Fast growing and operating from multiple locations Operating from a single location
What Call Quality does it provide? Average call quality Higher call quality
Network ConnectionRequires high-speed Internet Requires termination hardware and phone connection
What is the cost of installation? No initial investment Huge hardware investment
What are the platform features? Phone, chat, message, audio & video conferencing from anywhere, anytime, any device Can make phone calls only from fixed locations
What is operational cost? Can be as low as $ 20 per month 4-5 times the SIP trunk cost

Which One is Right for Your Business?

Both SIP trunking and PRI have advantages and disadvantages. There are multiple factors you will want to use to evaluate your decision. Overall, it depends on your business requirements, goals, and existing network infrastructure.

Here are a few key considerations you will need to answer:

Do you have multiple locations?

SIP is a great fit for a business who have multiple locations. You will be able to route calls between different physical locations, no matter who far apart they are, plus you will have greater redundancy. PRI is better suited for businesses who operates from a single physical location

How important is call quality?

SIP provides decent call quality, but for some businesses, this might not be enough. PRI provides higher call quality and less chance of a call being dropped.

Are you growing quickly?

SIP trunk is a much better fit for fast-growing businesses. It can be scaled up very quickly and doesn’t require a massive investment in physical hardware to get started.

Do you have a reliable network connection?

SIP is entirely reliant on your network connection. So, if your network quality suffers during peak business hours, then you might want to upgrade your connection (if possible) or consider PRI. There is no best choice when it comes to PRI vs SIP trunking. Instead, it should be the best choice for your business. Take the above questions into account to evaluate your business needs before you make a decision.


PRI is a better fit for companies who need better call quality and works from a single location

SIP Trunk is a better fit for companies who are growing rapidly and work from multiple locations.

Choosing the right technology is crucial to a growing business. Take the uncertainty out of the equation by choosing a SIP technology provider that can scale to meet your business needs, whatever they may be at any given time.Call 1-855-301-5490 or fill out the form below to request a no-obligation quote from an 8x8 Product Specialist


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