Choosing a business phone service (whether a new one or a replacement) from the vast modern acronyms can be challenging. Nonetheless, two choices seem to stand out from the rest—the traditional telephony Primary Rate Interface (PRI) and the Voice-Over-IP (VoIP) systems that are conveyed over Session Initiation Protocol (SIP). While the two systems serve the same fundamental function of allowing employees at a business to receive and place phone calls, they differ in many ways. So SIP vs. PRI, which phone system better fits the needs of your business.

PRI vs. SIP Trunking

PRI and SIP are competing phone technologies with distinctive pros and cons. Understanding their features and how each of them works can help you choose the technology that fits your business better.

What is PRI Phone Service?

For decades, this T-1 transmission technology has been used extensively as an alternative to IP-based phone systems to support voice communications. It uses physically installed copper cables to convey multiple lines of data and voice through its interface standard. Its circuit entails 23 voice channels that support 23 simultaneous calls, and a single data channel for the call-related functionality.
The voice calls are transmitted as electrical pulses and channeled through the conventional telecommunication carriers. Thus, PRI requires collaboration between on-site cabling service providers and the telecom company to add lines or upgrade equipment.

Pros of PRI

Having the PRI technology in your business affords you:
• High quality due to the established line structure
• Voice calls that don’t rely on data bandwidth
• Redundancy since you can add a second PRI circuit for failover

Cons of PRI

Some of the disadvantages of using PRI include:
• It is costly to upgrade, implement, and keep up with the required monthly phone service
• For voice calls, particularly the long distance, you may need long-term contracts with traditional telecommunication companies
• Has a fixed call capacity that can be acquired only in 23 line units
• It is slow to scale and can be time-consuming when modifying the infrastructure to integrate the copper cables

PRI Technology Best Cases Application

PRI can be ideal for businesses with limited access to the fiber-optic internet but have an existing installed legacy PRI infrastructure. Moreover, firms with sufficient bandwidth to support IP phones can benefit from a hybrid of PRI and SIP, where you retain the PRI technology for local calls and use the SIP for multimedia communications to save the costs on international or long distance calling.

What is SIP Phone Service?

Business SIP Trunks is a technological standard that places and ends calls between a VoIP and another phone number. Basically, it transmits voice calls in form of data or other forms of multimedia communications. Besides, it can transmit Unified Communications such as SMS, video conferencing and data.
A SIP trunk can be hosted and maintained by a vendor who will manage the transmission of voice data. Thus, contrary to the PRI, SIP excludes the need for traditional telephone infrastructure including the circuits.

Pros of SIP Trunking

Firms are switching to SIP Trunks because:
• You only pay for the capacity needed since it is sold on a per-channel and on-demand basis
• In the event of data connectivity loss, it offers failover to the mobile phones
• Can be integrated with the cloud implementation as well as multi-media communications to ensure productivity and collaboration
• Entails rich mobile features that offer support for remote workers in multiple sites

Cons of SIP

Some of the Business SIP Trunks drawbacks are:
• Requires internet bandwidth mostly the fiber internet for the quality of service
• The quality of services in terms extensibility and quality may vary widely
• It needs ample network information security including firewalls to avoid cyber-crimes

SIP Technology Best Cases Application

The SIP cost-effective aspect makes it an ideal technology for call centers as well as organizations with long distance and international calls. Mobile businesses or those in different locations can significantly benefit from the increased mobility since it will support remote workers.
By adding or removing the on-demand features, it can be an excellent scale for business communications efficiency. Also, allowing for the Unified Communications as a Service (UCaaS) and the Hosted, Multi-Channel Cloud Communications eases the burden of phone system management.

PRI vs. SIP- 4 Key Business Considerations

Before making a choice between SIP vs. PRI technology, it is crucial for every business to make the following considerations:

The Cost

Although the cost-saving aspect can vary from one vendor to the other, SIP is generally 30%-40% cheaper than PRI. That’s because, business SIP Trunks allows organizations to scale the system, increase features, and make long distance calls at an affordable rate. Nonetheless, in some very rare instances, businesses that are not going to adopt advanced communication technologies, retaining an existing PRI system can be a cost-saving choice.

Information security

PRI is deemed more secure, but the copper cabling can pose some information security risks such as interception and interference. For the SIP Trunking, businesses without on-site information security expertise may be vulnerable to the security risks. That’s because SIP information security requires an expert to run the consumer-class VoIP over public internet connectivity and gain adequate network security.

The Flexibility

Flexibility and scalability are the most significant cons of PRI and yet the biggest pros of SIP. The PRI requires an organization to buy additional 24 lines user capacity and may have to wait for a longer time for the high-cost infrastructure upgrades. With the SIP, you can just add a service line to accommodate temporary usage and remove it whenever it is not needed. Also, firms can unlock usage-paid billing upon demand.

Reliability aspect

While PRI is generally reliable, firms can lose access to phone services in case of a damaged component of the infrastructure. For instance, the copper-based phone cabling, which is prone to risks such as vandalism, inclement weather, or infrastructure degradation? On the other hand, SIP can be reliable provided that the business has the grit to invest in weather-resistant fiber-optic internet connectivity and collaborates with a credible vendor. The SIP mobile failover is also dependable since you can use established phone lines whenever there is a loss of data connectivity on the enterprise.

SIP vs. PRI – Which Is Best For My Business?

Ultimately, the best choice depends on your business, your desires, goals in adopting advancing communication and collaboration technologies. Some firms are opting for SIP; others remain with the legacy PRI phone systems, and others prefer using the hybrid solutions that blend the two systems into one.

Get In Touch

If you are ready to stop worrying about your phones - and get seamless communication with your customers and your employees - contact us now.


1411 Falls Ave E, Suite 209
Twin Falls, ID 83301

Tel: 208.735.8999


Twin Falls, Idaho
Boise, Idaho
Houston, Texas
Long Island, New York

*We Serve The Entire US & Canada*


Follow us