What Is PRI, and How Is It Different from SIP Trunking?

Primary Rate Interface (PRI) and Session Initiation Protocol (SIP) trunking are different methods that enable businesses to connect to the Public Switched Telephone Network (PSTN). The answer to the question “What is PRI?” is simple: it is the traditional analog landline phone system. Many companies use it together with Private Branch Exchange (PBX) phone systems. PRI made it possible for businesses to handle multiple, concurrent voice calls. 

SIP trunking, on the other hand, is a newer technology that enables digital communication transmissions. In digital communications, voice calls are transmitted as data. A SIP trunk connects businesses to the PSTN virtually and sends the data via packet-switching. In other words, it does not involve phone lines but instead leverages broadband internet connections and Voice Over Internet Protocol (VoIP) technology. 

Related: What is a SIP Service Provider?

As a business owner, you may be trying to decide on the most reliable and economical method for keeping your vendors, customers, and employees connected or you may be considering the advantages of becoming a reseller. You’ve come to the right place. There is much to unpack, so let’s start learning more about the differences between PRI and SIP trunking.

What Is PRI Trunking?

PRI is the traditional phone system that has been widely used since the 1980s. It uses the Integrated Services Digital Network (ISDN) to deliver multiple lines of voice and data through one physical line of a business’s Private Branch Exchange (PBX) via circuit-switching. A PRI trunk is a single copper landline that accommodates up to 23 separate voice, data, or video channels. Data is transmitted through the lines electronically. 

Advantages of PRI

Though now an aging technology, PRI was once the gold standard for business communications. Some benefits of PRI include:

• Dedicated connection – Some customers feel PRI has a higher overall service quality because it isn’t a network technology. The transmissions are sent over a dedicated line rather than competing for internet bandwidth.
• Security – Since PRI is a private network, calls are not at risk for potential interference or hacking by cybercriminals.
• Capacity – PRI is considered a high-capacity service that is carried on T1 lines— a dedicated connection between a service provider and a client.

Disadvantages of PRI

Though there are compelling advantages to PRI, there are also some considerable drawbacks:

• Cost – PRI comes with considerable costs for installation, service, infrastructure, hardware, and maintenance, particularly when compared to SIP.
• Scalability – PRI is not easily scalable. If you want to add a new phone line or there is a line issue, then your provider will need to send a technician to make the changes.
• Infrastructure and maintenance – PRI technology requires physical infrastructure and needs to be serviced by a telco for troubleshooting and upgrading.
• Longevity – The outlook for physical copper lines is bleak. As of August 2022, the Federal Communications Commission instituted a landline service shutdown in the United States, meaning providers are no longer required to install or maintain copper cables. This will facilitate the installation and adoption of more internet fiber-optic cables and next-generation technology while removing the burden of legacy technology maintenance from providers. The FCC Landline Shutdown Order 19-72 means that landline services will eventually be discontinued nationwide. 

What Is SIP Trunking?

SIP trunks facilitate communications between businesses, their vendors, customers, and employees. They rely on your existing internet connection. SIP trunking lets you rapidly transmit high-quality voice, video, text, images, and documents via a virtual network and Voice over Internet Protocol (VoIP). VoIP technology is what powers applications like Facebook Messenger, Zoom, and Skype. 

A SIP trunk is comprised of channels. Think of the virtual channels as the modern version of traditional phone lines, except each virtual channel handles two calls simultaneously—one incoming, and one outgoing—whereas traditional landlines only handle one call each. SIP technology works over a WiFi network as opposed to traditional telephony methods like PRI. 

SIP setup is easy and fast. Since it is virtual, it can be done very quickly. It allows any business to make voice or video calls, share information, and access software on any number of VoIP-compatible phones, smartphones, computers, and tablets. With most providers, you can add or remove features and channels easily via an online dashboard. 

SIP technology also makes it easy for those looking to offer their clients additional services that don’t require a significant initial investment. With the right SIP reselling partner, businesses can start offering SIP trunking under their own brand. Adding more value for your customers and creating a new, recurring revenue stream is fast and easy. 

Advantages of SIP

SIP trunking provides many valuable benefits:

• Cost – Often SIP is much cheaper than PRI and comes with easy-to-use administration portals for easy management. 
• Scalability – Many businesses appreciate the flexibility of SIP providers. Similarly to PRI, SIP allows you to have multiple voice lines within an organization. However, it is far easier and faster for SIP providers to add a new line when requested. They  are also able to quickly and virtually troubleshoot any problems. 
• Infrastructure and maintenance – Another advantage of SIP trunking is that there is no hardware required because it is a virtual service. This means that there aren’t any upfront hardware costs, and you can get to work straight away once it is set up.  Businesses don’t need an existing PBX, as most SIP providers offer a hosted one.
• Integration – A further benefit is that SIP trunking can be integrated with existing PRI trunks. This is ideal if you want to upgrade or have both PRI and SIP trunks.
• Disaster recovery and failover – SIP trunks allow you to take advantage of multiple providers, giving you more failover capabilities in case of a provider or network outage.
• Consolidated network management – Since SIP trunking operates on your data network, it allows you to consolidate your communications into one single network. 
• Reselling opportunities – With the right provider, you have the opportunity for creating additional, recurring revenue by becoming a SIP reseller. 

Related: A Beginner’s Guide to Becoming a Successful SIP Trunks Reseller

Are There Disadvantages of SIP?

While the advantages are impressive, there are still some other considerations to address with SIP trunking: 

• Compatibility with traditional analog phones – SIP and VoIP technology require newer technology and VoIP-compatible phone systems. This could be considered low risk given the increasing rarity of analog phones, with the exception of older, established businesses that may still use a traditional PBX system. 
• Internet outages – Like electricity, internet service is subject to very occasional outages. Though there is no way to completely eliminate the risks of this happening, they can be mitigated by choosing a reliable high-speed broadband internet provider with failover capabilities to prevent communication issues and maintain stable connections.
• Security – Digital security is of primary concern to any business reliant on the internet. However, leveraging SIP trunking from a trusted provider comes with some built-in security protections, such as end-to-end SIP encryption. When combined with your enterprise security protocols, your data is protected from cyber threats.

How to Choose Between PRI and SIP

If you are looking for a cost-effective phone system that accommodates today’s remote workforce, then SIP might be right for you. SIP trunking allows you to add a variety of features, place national and international calls, and scale your system at a fraction of the cost of PRI. If information security is high on your priority list when choosing a phone system, then SIP with a secure network plan could be a good choice.

SIP trunking is definitely fitting if scalability is a concern. Organizations that rely on SIP can add new lines as necessary and remove them just as easily if they are no longer needed, by simply making a quick change to their plan. It also provides flexibility with usage-paid billing. This means you only pay for what you need.

Some believe the answer to the question “What is PRI?” is simply “the traditional, most secure phone system.” While there is some security advantage to having a dedicated landline, modern businesses operate under strict internet security protocols to ensure data security and integrity remain paramount. 

Regardless of where you land on whether PRI or SIP trunking is more secure, new regulations mean that there is no longer any requirement for providers to install or maintain the traditional copper lines used for PRI, and a shift to reliable SIP services continues to grow. AT&T, one of the nation’s largest providers, announced that by 2025, it would reduce its copper footprint by 50%. 

PRI vs SIP: Which One is Best?

So, which is the best choice for you between PRI and SIP? As you research “What is PRI?” versus “What is SIP?”, you can start to compare what different SIP and PRI providers offer in order to make the best decision for your business.

SIPTRUNK is a trusted provider of high-quality SIP trunking and SIP reselling. We are confident that you’ll recognize the many advantages of SIP trunking for you and your customers. Get started today on your new revenue stream as a SIP reseller with SIPTRUNK.