different apples and oranges 1

PRI vs. SIP Services – What’s the Difference?

different-apples and orangesWhen it comes to voice communications for your business, you have a couple of options. You can choose between PRI and SIP services. There are advantages and tradeoffs with each approach, so deciding which way to go requires a thoughtful analysis of the needs of your business. Here’s a closer look at each.

PRI (Primary Rate Interface)

PRI is a “smart”’ T1 connection. It is made up of 23 voice channels, and it supports 23 concurrent calls along with one data channel that handles Caller ID and other carrier functionality.  PRI lines are copper line connected directly to your building.


Because PRI lines are physical connections that don’t require an Internet connection, they are the best option for businesses in areas with inadequate bandwidth for Internet-based voice services.


What you give up with PRI lines is price, flexibility, and scalability. PRI lines are usually offered by traditional telecommunications carriers and are sold under long-term contracts for both local and long distance services. Because they are sold in groups of 23, businesses often end up with more capacity than necessary. If for example, you need 25 lines, you must purchase (and pay for) 46. The fact that a physical line must be added for each new group of lines also causes delays and additional expense.

SIP (Session Initiation Protocol)

SIP is a communications protocol that enables delivering voice and other unified communications services, like messaging and video, over the Internet. It eliminates the need for PRI lines by connecting to an IP-enabled PBX or cloud-based voice solution. SIP utilizes the same Internet network that supports data needs.


SIP services are usually offered at a lower initial price point than PRI lines, with most long distance calls included at no additional charge. SIP is sold one channel at a time and is offered on-demand, so businesses pay for only the amount of capacity that they need and can grow at any time. Also, if an emergency or power outage occurs at the business location, calls can easily be rerouted to other offices, mobile devices, or home phones, making the business more resilient and responsive. The best solutions include easy to use control panels so that even someone who is not a telecommunications expert can manage moves, adds, and other standard changes.


It is essential that businesses choosing SIP service have adequate Internet bandwidth to support both voice and data needs. This can be facilitated by using a router that has a feature called Quality of Service or QoS. OoS prioritizes voice traffic over data traffic to eliminate the problems of jitter and lag.

SIP is used with a PBX that is SIP or IP-enabled, or it can be used with an analog PBX system in conjunction with an Analog Telephony Adapter, that converts the analog signal to digital.

Finally, while most traditional telco carriers are alike, there are big differences in the services and support provided by the many SIP vendors out there. It is crucial that decision makers understand what they can expect regarding both service and cost before selecting a SIP provider.

While SIP is not right for every business, it is becoming increasingly popular because of its low cost, ease-of-use, and flexibility.

Free SIP Trunk in 60 Seconds

Related Posts


SIP Trunking Providers – What’s the Difference Between Them?

May 9, 2022

The workplace environment we are all familiar with has changed since the start of the…

Read More
Smiling young african man sitting coworking chatting by phone.

VoIP Server: Do You Need One?

April 20, 2022

Why Is a VoIP Server Important? Everything around us is going virtual. From the teleconferences,…

Read More
Woman in the office

SIP Trunking Basics: What Is a SIP Gateway?

March 15, 2022

Have you ever wondered how important a phone system is to conducting business effectively? Although…

Read More