Upgrading to SIP Trunking: What You Need to Know

Decisions about communications technology often leave businesses flooded with acronyms and a great deal of confusion about how each type of system functions for business purposes. Two acronyms that come up often in discussions are PRI and SIP trunking, which stand for Primary Rate Interface (PRI) and Session Initiation Protocol (SIP), respectively.

It’s common to ask what the differences are between these two technologies, and the simple answer is that SIP trunking is an improvement on PRI. If a more comprehensive understanding is necessary, the two options can be compared in terms of efficiency, capacity, and cost:

Efficiency: PRI was designed to bring voice and internet connectivity to businesses using a private branch exchange (PBX) system. The problem is that both voice and data transmissions were static through the connection and there was no way to earmark bandwidth for optimized use. The system allotted space for voice and data, no matter how much of each was being used at any given time. In addition, PRI had no vehicle for employing Quality of Service (QoS) rules that protect the quality of voice calls by prioritizing them over a data transmission.

SIP trunking solves each of these issues by introducing the ability to set policies that allocate bandwidth according to certain priorities, protecting the quality of voice calls and ensuring bandwidth is used efficiently.

Capacity: PRI was exciting technology, because it allowed a business to have 23 lines plus one Integrated Services Digital Network (ISDN) line. Because SIP trunking uses Voice over Internet Protocol (VoIP), the number of lines available are unlimited, rather than coming in units of 23 lines. This means that a company is able to expand and contract its access of telephone lines based on seasonality or other factors that affect phone use by having a set number of lines, but with a burstable expansion available when needed.

Cost: The initial costs of either type of phone system will be low, because both access the existing PBX system. The difference comes in with monthly charges, because the $300-400 monthly bill that comes from PRI is far higher than even the most expensive SIP trunking option. Calls between SIP clients are always free, so a company might see measurable cost savings just in their long-distance calls.

Comparing these two technologies seems a bit unfair, because they were never meant to compete with one another. In general, you won’t see PRI systems except in situations where a company has been successfully using it and doesn’t have a motivation to upgrade to SIP trunking. Some may want to consider moving to SIP trunking because of the QoS standards available and the cost savings that can result from the transition.

If you’re considering an upgrade to your communications technology, contact us at AMD Technology. We can help you determine the best solution for your business needs and for your budget.