Primary Rate Service PRS

Digital Connectivity For Your Evolving Voice, Video And Data Transport Needs

Link your PBX to the CenturyLink® advanced central office systems, which support digital connectivity, data file transfer, voice calls, fax transmission and video traffic. 

Businesses are built on connecting with customers and suppliers, and Primary Rate Service employs an established, worldwide telecommunication standard to foster powerful global connections. PRS is technology for today and tomorrow. 


Customer Flexibility

Bandwidth-on-demand provides exceptional flexibility with the functionality of multiple communication circuits at a comparable price.


Employs an established telecommunication standard that allows large data files to be digitally transferred locally or globally.

Fast Data Speeds

Bond channels to provide higher data speeds in increments of 64 Kbps. ISDN provides a clear, crisp communications connection where noise and bit errors are not a factor. Lines and host computers get fast, reliable backup.

Borderless Communications

Share all types of information with virtually anyone, anytime, anywhere.


Offers industry-leading, Tier II technical support including network monitoring (four-hour service window) and 24/7 technical support.

Flexible Capacity

Allocate additional channels to an application in any multiple of 64 Kbps.


Supports simultaneous Internet access, data file transfer, voice calls, fax transmission and video traffic.


Voice and Data Transmissions Employ Crystal-Clear Channels

Any Channel Can Carry Any Type of Connection, Eliminating the Need for Single-Purpose Trunks such as Direct Outward Dial (DOD), Dedicated Video and Data Private Lines

Features Caller ID, Direct Inward Dialing (DID) and Rapid Call Setup

Regional Pricing Options Available for Remote Locations

Channel Bonding Used for Added Cost Efficiency, Rapid Scalability and Added Control and Flexibility

Functionality Across Standard Analog Four-Wire and Fiber Optic Circuits Employs Technology That Is Both Widely Deployed and Cost Effective

How It Works

PRS is a switched-trunk service based on Integrated Services Digital Network (ISDN) that integrates voice, video and data applications simultaneously over the same DS-1 facility. It combines 23 circuit switched voice and data channels offering bandwidth up to 1.544 Mbps with one D channel used for call setup, signaling and network control. This seamless communications system speeds and smoothes the flow of information without the expense of dedicated lines, modems and special cabling. As your needs grow, the functionality of PRS will provide digital connectivity that is feature-rich, flexible and widely available.

The DS-1 based service uses the 23 B channels to carry all user data (voice, data and video) and one D channel to carry call supervisory information such as call setup, Caller ID, routing information and channel designations. Because of the D channels control, the B channels are free to carry all information bits. This type of signaling, in which the information is sent over a band separate from the actual call, is known as out-of-band signaling. PRS combines the features of three types of digital switching: circuit switching, packet switching (transmitting data in individual packets) and common channel switching using Signaling System 7 (SS7) to vary the means of transmission as necessary.

Network Maps

The CenturyLink network covers the continental United States and has one of the largest fiber footprints. Internationally, we provide coverage to hundreds of destinations.

More Services and Solutions for You

Managed Office

Internet, voice and business applications—including Microsoft® Office 365—in one complete solution.

Hosted VoIP

Communicate faster and in more places without the expense of an onsite phone system.

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