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What is the difference between PRI and SIP trunk?

  • A PRI trunk uses the Primary Rate Interface standard to transmit as many as 23 voice channels over a single copper telephone wire. A PRI trunk provides a physical connection to the PSTN and uses a circuit-switched model to make connections.
  • A SIP trunk uses Session Initiation Protocol to transmit data and can scale easily to accommodate as many voice and data channels as an organization requires. A SIP trunk provides a virtual connection to the PSTN and transmits voice calls as data, using a packet-switched model to make connections.
     

When considering an enterprise phone system, the selection often comes down to a choice between a PRI and SIP system. But what is the difference between PRI and SIP trunk options, and what advantages and disadvantages to both systems present? Here’s a short overview on “What is the difference between PRI and SIP trunk?” that provides some detail.

What is the difference between PRI and SIP trunk?

A Primary Rate Interface system, or PRI trunk, provides a physical connection to the Public Switched Telephone Network (PSTN), while a SIP trunk offers a virtual connection to the PSTN. A PRI trunk is a single line, usually a T-1 connection in North America, with 23 voice channels transmitted as electrical signals over copper wire, using a circuit-switched model for making voice connections. A SIP trunk sends voice calls as data over an existing ethernet or fiber connection. A SIP trunk supports Voiceover Internet Protocol (VoIP) telephony and uses a packet switching model for making connections.

What is the difference between PRI and SIP trunk for scalability?

Because each PRI trunk line provides 23 channels, scaling up requires a business to order additional PRI trunk lines which may take 2 to 3 weeks to deploy. A SIP trunk can be ordered with any number of increments and can be deployed in days or hours, providing a more flexible telephony technology.

What is the difference between PRI and SIP trunk in security?

A PRI trunk is often thought to be more secure than a SIP trunk, since the latter may be vulnerable to security risks when running VoIP over public Internet connectivity. However, with adequate network security, a SIP trunk may be just as or more secure than a PRI trunk.

What is the difference between PRI and SIP trunk for QoS?

Because a PRI trunk uses a dedicated connection for voice transmission, it tends to offer higher Quality of Service than a SIP trunk, which often must compete for bandwidth with other data sources.

What is the difference between PRI and SIP trunk in costs?

The cost of a SIP trunk may be as much as 30 to 40% cheaper than the cost of a PRI trunk.

What is the difference between PRI and SIP trunk in terms of reliability?

While PRI is considered to be highly reliable, the copper wires in a PRI trunk may be damaged by weather, vandalism and aging infrastructure. A SIP trunk offers greater redundancy and is very resistant to weather and other types of damage, especially when provided as part of a fiber-optic connectivity.

What is the difference between PRI and SIP trunk with Spectrum Enterprise?

As a leading provider of fiber solutions to America’s largest businesses, Spectrum Enterprise offers both PRI trunk and SIP trunk solutions, with interoperable and feature-rich support for fiber solutions for premise-based phone systems. Spectrum Enterprise voice technology provides next-generation communications solutions with superior call quality and cost advantages, along with collaboration features to keep employees and clients connected.

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