PRI vs. SIP — What Makes More Sense for Your Business?

Voice communication connects people to your business. 



Customers and partners rely on it day in and day out. And you, in turn, rely on  business communication tools  to keep them connected. These systems cater to the needs of your teams, customers, and partners. When these needs evolve, you must adapt.



Businesses often compare Primary Rate Interface (PRI) and Session Initiation Protocol (SIP) when thinking about agility and scalability. They both help you connect to the telephone network but in entirely different ways.



One is a legacy product from a local telephone company, while the other is much easier to scale. Dive deeper to know which technology best aligns with your needs.



What Is PRI?



PRI is a telecommunication standard that carries voice and data transmissions between a network and a user. It uses physical copper wires to digitally connect your business with the public switched telephone network ( PSTN ).



PSTN aggregates national, regional, and local telephone operators. Whenever someone calls you, the call enters a private branch exchange (PBX). An on-premises  PBX  is a private telephone network professionals use within an organization to communicate with external and internal callers.



Network diagram showing Primary Rate Interface in an office network (via  GCG )


When the call reaches the PBX, an integrated services delivery network line or an analog copper line transmits to the receiver. However, if the receiver is busy, the call will go to a voicemail. This helps businesses prevent callers from listening to a busy tone.



Large organizations and enterprises often use PRI lines to address the challenges of traditional phone service in business. It’s been the backbone of  enterprise telephony  for many years.



PRI features



Below are some notable features of the PRI telecommunication standard:




Fixed number of voice channels:  A PRI phone supports 23 bearer voice or data transmission channels, which means 23 communications can happen at the same time. These channels allow multiple calls simultaneously and transmit voice, data, and video on the same line. The data transmission occurs at 64 Kbps per channel. It uplifts speed, makes communication reliable, and increases the security of a business voice communication system.



Dedicated lines for voice and data:  A PRI trunk offers a consistent level of service, and voice and data connection lines don’t traverse over the Internet but rely on the PSTN for connectivity. 




PRI requirements



You need PRI-compatible equipment, such as a PRI gateway or a PBX with a PRI card, to interface with digital lines. It can work with analog or private automatic branch exchange systems.



Although PRI allows 23 simultaneous calls, you can increase the capability by adding additional PRI circuits when the number of calls increases.



What Is SIP?



SIP connects your Internet Protocol (IP) PBX to the internet. It lets you make and receive calls over the Internet.



SIP trunking  is a scalable way to facilitate voice calls in businesses. Trunking consolidates multiple communication channels into a single virtual connection. It uses resources effectively while connecting to a telephone network.