PRI and SIP Trunking – What, another telephony thing to keep track of? By now, you’ve probably encountered enough acronyms referencing obscure technology to make you a competitive Jeopardy contestant. But if you’re in the market for voice services for your business or organization, knowing this stuff can be crucial to identifying future bottlenecks down the road.

Most of the passionate debate among telecommunications professionals will boil down to two phone systems: Primary Rate Interface (PRI) and VoIP (which is delivered over Session Initiation Protocol, or SIP). While either system will guarantee you a comprehensive voice solution, there are pros and cons to selecting either protocol. First, let’s put on our history-buff hats, and learn about how these systems developed.

A Brief Overview of How Both Services Came to Be…

In the beginning, there were insulated copper wires. These operated as part of the Public Switched Telephone Network (Another acronym coming your way – it’s PTSN for short). In due time, the telephony industry was bracing itself for the coming digital revolution, and by the 2000s, most businesses had been switched over to PRI lines. This was a big deal, because it allowed companies to make and receive 23 simultaneous calls over the same line, whereas analog only permitted one call at a time.
At the same that everyone was migrating over to PRI, the internet was building in popularity. Thus, a means of phoning people over the world wide web was born. Maybe you’ve heard of VoIP services before, but SIP is essentially the vector through which VoIP functions. SIP Trunking is a key protocol that sets up and tears down real-time sessions between two endpoints, allowing for an almost unlimited number of simultaneous phone calls – assuming you have the bandwidth to support that many. SIP is rapidly replacing PRI as the dominant protocol for business telecommunications, partially because VoIP is relatively affordable and offers several perks (which we’ll get into shortly).

How does PRI work?

Primary Rate Interface works using T-1 transmission technology, an interface standard that provides 23 voice channels through preexisting copper lines constructed during analog’s golden years. They usually have an additional data channel to support call-related functionality like Caller ID. Calls are submitted as electrical pulses and routed through the telecommunications carriers we all know and love.

The primary issue that arises with PRI is when an office need more 23 lines. Another PRI must be installed, requiring more lines, maintenance, a new PBX, or an additional PBX altogether. Even if you only need a couple more lines, there’s no other way to add voice channels on an individual basis.

How does SIP work?

A SIP trunk allows you to use a data connection to transmit your voice to your carrier’s data, or SIP, network. The carrier then patches it through to its outgoing destination. These connections are virtual, meaning they’re determined by bandwidth rather than physical hardware or electrical circuits.

A few benefits? A multi-party phone call counts as a single SIP channel. And scaling up is matter of getting on the phone with your service provider, who can process your request in as little as a couple of hours.

Which is the best choice for me?

VoIP Phone

VoIP Phone

Now, the first assumption might be go for the latest and greatest telephonic technology, but don’t jump the gun on such a huge decision. There are drawbacks to both which should be considered. And if you’re feeling really torn about letting the benefits of either go, you can always set up a hybrid system, which combines the best of both worlds.

Pros to PRI

  • Data bandwidth isn’t a concern with voice calls. That means fewer dropped calls, less network instability, and more certainty when picking up the phone.
  • Because each channel takes up a dedicated, analog line, call quality is superior (though some VoIP providers will argue against this, since so many factors, like microphone placement and phone quality, make a difference).
  • In the event of a service outage, many institutions have a backup PRI line that can serve as a temporary interface.
  • They’re less prone to hacking, and generally thought of as more secure than a VoIP service.
  • Data bandwidth isn’t a concern with voice calls. That means fewer dropped calls, less network instability, and more certainty when picking up the phone.

We should note here that CTS provisions our SIP Trunks to include all of these “Pros to PRI” items. If you’re in our coverage area, give us a call and one of our communications consultants can help determine the proper choice for your business.

Cons to PRI

  • To expand PRI lines, you’re looking at an increase in monthly phone costs, plus initial implementation costs and occasional maintenance. Not cheap, by any stretch of the imagination.
  • Larger telecom companies might have a stranglehold on your locality. This leads to higher price tags and long-term contracts for local and long-distance calling.
  • We can’t stress the 23-line-at-a-time capacity enough. If you have a stable business size, this won’t matter too much. But if you’re a fresh start-up or a fledgling company expanding to multiple locations, you might want to look elsewhere. PRI is slow to scale, often requiring weeks of waiting.

Pros to SIP

  • Includes rich mobile features and mobile-centric design. Need text or email alerts when a call comes in while you’re out of the office? Many VoIP providers offer such services.
  • Managed IT support and solutions are often coupled with SIP services.
  • Includes easy-to-use administrative portals in an attractive interface.
  • Typically cheaper than PRI phone services overall. Less maintenance is required, especially if cloud-based VoIP services are used.
  • Infinitely scalable. Sold by telecom companies on a per-channel or per-minute basis, so you won’t have unused lines or overloaded PBXs anytime soon.

Cons to SIP

  • Requires a large amount of bandwidth. Fiber optic cable is the preferred choice for large and medium-size businesses.
  • If improperly configured to the network, voice quality issues can occur.
  • Needs network information security, such as firewalls, to prevent cybercrime.

To Find the Perfect Voice Solution for Your Business, Contact CTS Telecom Today.

Curious about what an SIP or a PRI can do for you?  Schedule a free demonstration courtesy of CTS Telecom. We have an array of voice services for all applications and budgets. And if you’re looking for an all-in-one solution, we offer colocation, voice, internet, cloud services, and data transport. We invite you to discover how CTS Telecom can take care of your business’s needs. To get started, contact us today.