The Primary Rate Interface (PRI) is a telecommunications interface standard primarily used in the Integrated Services Digital Networks (ISDN) and is primarily a service provided to large enterprise users T1 or E1 PRI lines between service stations on the basis of the country of the telecommunications provider’s central office and Customer Endpoint is a high-capacity ported service.

What is a PRI?

The Primary Rate Interface, or PRI, is a vendor-less communication system that allows organizations to use a copper-to-wired connection to transfer data, video, or files using a network architecture.

The PRI system offers up to 23 B channels on a single telephone line. With a PRI-compliant communications solution, multiple users can have ranges and numbers on the same connection. Physically, the PRI line consists of two pairs of copper wires that provide duplex capability. The duplex feature lets you access secure data transmission from the other two wires.

PRI stands for Integrated Services Digital Network (ISDN). There are two types viz.

• The Basic Rate Interface (BRI) solution is designed for home and small business use. A BRI system consists of B and D channels, but unlike PRI lines, the B channels can accommodate only one communication session.
• Due to the number of simultaneous B-channel lines, the prime rate interface is a more cost-effective solution for enterprises.

How Does a PRI Work & Features of a PRI line?

Do you know what a PRI is? You should also know how the PRI network works. PRI can add up to 23 lines to the network dialing configuration. It can be up to 30 lines for channel E1.

Because many lines are available on the PRI network, the company can easily scale as needed. Depending on the needs of the typesetting company, lines can be used or left blank.

PRI networks do not operate on the same bandwidth as Voip channels. PRI circuits allow teams to deliver updates faster because the system is not dependent on bandwidth.

The PRI versus SIP discussion looks at the availability of multiple lines.

Since the PRI line aimed to provide the highest quality sound and video, features include:

• The ability to transmit up to 23 different communications simultaneously through various channels such as telephone, video, and data transmission.
• Premium copper wire lines for seamless connectivity throughout.
• Multi-format compatibility provides business end-user flexibility.
• Manage various connections across analog systems and PBX configurations.
• Providing different numbers of channels and bit rates in different geographic locations because it is the physical connection of the system through T1 and E1

Types of PRI Channels

Both types of PRI channels primarily depend on geographical location along the PRI line.

T1 Trunk Line,

The common PRI line in the United States and Canada, is the T1 mainline, which uses 24 channels. One of these names is reserved for part identification and is known as the “D channel” or delta channel.

There are other carrier channels that contain voice data to be transmitted. Telecommunications provides service providers with 23 different telephone lines.

There will be two pairs of wires on the T1 line, copper. The T1 trunk line has a transmit/receive speed of about 1.544 Mbps.

E1 Trunk Line

The E1 trunk line is similar to the T1 trunk line but for European countries. Unlike the T1 channel, the E1 trunk has 32 channels providing 2D channels, and another 30 are Bearers or B-Channels.

Like the T1 line, the E1 line will have two copper wires. The transmit/receive speed for trunk E1 is about 2.048 Mbps.

Advantages and Disadvantages of PRI

PRIs: The Good

Primary Rate Interface is an end-to-end managed service that delivers great value once configured. They require investment in fixed infrastructure, but once the infrastructure is in place, many benefits will be gained from the primary rate interface.

• Reliability

The primary rate interface lines are powered by the central office to provide stability, allowing them to remain in place during power outages. It’s also digital, making troubleshooting simpler and more effective than an analog trunk.

• Security

An analog box is a child’s toy that can be operated without technical knowledge. If you’re an analog enthusiast, someone might spy on you with a homemade bug that costs about $7 to make. You can easily find YouTube tutorials on how to do it. The digital nature of PRI provides an additional layer of security and privacy for your communications.

• Speed

High-quality calls made through the primary rate interface are established much faster due to the dedicated line structure.

• E911 Compliance

The PRI environment can provide granular caller location information to the 911 call center. This will include the caller’s building address, its floor, and the subnet of that floor so that emergency responders can locate the caller quickly and accurately.

SIP trunk operators often do not provide this granular information. This would be a problem on college campuses, for example. If someone calls 911 from a campus with a SIP trunk, the 911 center will see that the call is from the university campus, but not which building, which floor, and so on.

• Straightforward billing

Your accounting department will thank you, and with the primary rate interface, you’ll be billed for 23 different phone lines instead of one.

PRIs: The Bad

• Reliance on physical components

PRI requires investment in fixed infrastructure, which can be time-consuming and expensive. Each circuit will require physical and hardware connections to complete the connection. Because of this requirement, scaling the system will require the installation of additional hardware and new circuitry.

What are the Pros and Cons of PRI?

Features of Primary Rate Interface

To understand how these communication systems work, it is first necessary to understand their function. The main features of the PRI system are:

1. The line consists of two copper wires connecting the supplier and the user.

2. You can have 23 B channels on one phone line. And with that, businesses can have multiple extensions and phone numbers with a single connection.

3. Each channel has 64 kbps for data transfer.

4. It can connect two PBX or PBX systems and work with an IP PBX system.

PRI vs. Hosted VoIP vs. SIP Trunking

Today, most businesses have adopted cloud VoIP solutions or hosted VoIP solutions. Hosted VoIP means that your service provider hosts your telephony solution and handles all your software and maintenance needs. All you have to do is use the service. You don’t have to worry about buying hardware and software, getting maintenance from a professional IT team, etc. This saves your company communication, and IT costs.

SIP trunking is a Session Initiation Protocol (SIP) feature that allows voice communications to be transmitted over a data network. SIP trunking works like POTS, except the phone lines, are virtual rather than standard copper lines. And your phone system connects to your provider through your internet connection. SIP trunking is often used as an alternative to POTS and PRI systems.

Unlike VoIP and SIP trunks, PRI does not rely on Internet bandwidth for transmission and therefore does not suffer from jitter or packet loss. However, there are limitations in terms of scalability, mobility, and available features.

Here is a chart to illustrate the differences between these business phone systems:

Alternatives to PRI Circuits

In addition to the primary rate interface, three main options use the power of technology and innovation to bypass this telecommunications loop.

POTS aka PSTN

PSTN (Public Switched Telephone Network) or POTS (Plain Old Telephone Service) is a standard landline telephone service. This old traditional landline phone is connected to a copper wire that dials the handset and connects it to the dialer. This cable powers the device and also enhances connectivity for the user.

VOIP

VoIP stands for Voice over Internet Protocol, which uses the power of the Internet to make voice calls to devices. VoIP is a state-of-the-art solution for the modern world. VoIP uses a high-speed Internet connection to make calls instead of a regular dial-up connection.

SIP

SIP, or Session Initiation Protocol, is the signaling protocol that makes VoIP possible by handling the actual elements of the call.

Supports video conferencing, instant messaging, and multimedia content delivery. Connect a private or local telephone system directly to the public telephone network.

You may think that SIP is similar to POTS. Contrary to popular belief, SIP has no physical phone lines. Instead, SIP phone lines are virtual.

PRI vs. PSTN: Which is better?

Voice Quality

PRI uses trunk lines 23 to 32 to connect to dedicated equipment via copper wire. On the other hand, the PSTN runs on a single device over a copper wire.

Thus, it can be safely argued that PRI is superior in voice quality with data packets transmitted over the channel.

Cost-Effective

PRI is by far the winner of this new test because PRI has multiple trunk lines across a link. However, traditional landline telephony is limited to one connection at a time.

DID (Direct Inward Dialling/Calling)

Both telecommunication services have direct dial-in features, enabling a seamless connection between the provider and the customer. So don’t wait any longer in line to contact the person you need to talk to.

Automated Call Distribution

PRI and PSTN provide ACDs to users. However, the PRI service ACD is more sophisticated than the PSTN. This is because PRI has good interoperability.

Communication Features

Since POTS or PSTN is a landline connection, it can only be used to call facilities. However, PRI has communication services such as voice, video, data, and fax. You can then decide which primary rate interface wins.

Security

PRI provides a higher level of security for calls over the PSTN because the network is more sophisticated and uses better calling technology. This makes it difficult for anyone to break into the PRI network.

PRI vs. SIP Trunking: Which is Better?

Reliability

SIP trunking provides a reliable solution with an excellent scalability option. In other words, avoiding difficult situations with SIP trunking is easier than with PRI. Routing is simpler with SIP than with PRI.

Quality

The primary concern is overall call quality and voice clarity. While SIP trunks use the Internet for calls, PRI uses copper wires for transmission. If the Internet is strong, SIP will provide HD-quality calls, videos, and data transfers. But PRI will, in most cases, deliver the same sound quality as Potts.

Hardware

SIP trunking requires a SIP server, broadband, and internet connection. On the other hand, there should be copper wire everywhere. You also need to purchase more devices to use the PRI network.

Cost

For at least 23 connections, the initial PRI cost due to physical connections is moderate to high. With international calling, troubleshooting, and local connections, the cost of running a PRI loop is also messy. But it is significantly weaker than SIP trunking, where much pocket money is spent on the server. However, SIP trunk costs range from moderate to high.

Flexibility

Since SIP provides separate circuits for communication, the scalability and flexibility of SIP trunking are much better than a PRI line. When you plan to expand your business, you will need at least 23 new connections for the PRI line. This makes SIP trunking easier to use.

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PRI vs. Hosted VoIP: Detailed Comparison

Reliability

Reliability for PRI depends primarily on physical connections and hardware. However, there are no physical equipment issues with hosted VoIP. Similar to VoIP calls over the Internet, the service provider takes care of maintaining the Internet. This gives the network better reliability because the Internet got better long ago.

Cost

Speaking of initial circuit setup costs, hosted VoIP only requires an Internet connection and can be skipped service. Ongoing maintenance costs and monthly rates for Internet calling services like VoIP are much lower because the Internet is cheaper today. On the other hand, get to know PRI quickly.

Flexibility

PRI takes a long time to get started because of the time involved in the initial setup. Also, as you know, PRI must get a certain number of mass channels for one line. This is not the case with hosted VoIP.

The same is not true for hosted VoIP.

You can roll out your service in hours, and the ability to add a few more connections is quick and easy with monthly ISP plan upgrades.

Quality

The voice quality with video calls in Hosted VoIP is very clear. Besides calls and HD video, data transfer is also fast.

Here PRI goes behind the scenes as information is transferred through physical lines against clouds and signals. Often voices on PRI lines sound distant.

Hardware

Hosted VoIP requires only the critical components your employees will use to make calls. You need a router for an internet connection to get more than that. On the other hand, VoIP differs from both PRI in that PRI requires a physical connection and an internal device. So the whole process involves a lot of material. This makes the problem a little harder to solve.

Final Thoughts

It is important for companies to adopt new communication technologies and agile infrastructure to keep up with the changing times.

So the decision to switch to something more dynamic and cheaper, like hosted VoIP, is easy, as opposed to PRI.

Whether you want to build a new communications ecosystem or upgrade an existing one, hosted VoIP can be the ideal solution, as it will meet all your needs and exceed your expectations.