Wholesale: Products & Services

2-Wire Frame Relay Service (2-Wire FRS) V9.0

History Log

NOTE: 2-Wire Frame Relay Service (2-Wire FRS) was Grandparented in December of 2000 and is no longer available to order as a new service.

Product Description

CenturyLink's retail telecommunications service, 2-Wire Frame Relay Service (2-Wire FRS) is available for resale by Competitive Local Exchange Carriers (CLECs) to end-user customers. Additional information about resale of CenturyLink's retail services can be found in the General Resale Product Catalog (PCAT).

This web page assumes that you are familiar with Frame Relay Service (FRS) and Integrated Services Digital Network Basic Rate Interface (ISDN-BRI). Should you require FRS or ISDN-BRI information, please refer to the Frame Relay Service or the ISDN-BRI Product Catalogs (PCAT).

With a 2-Wire FRS access link over a 2-wire local loop, your end-user can access the Advanced Communication Service (ACS) FRS Network over the existing twisted copper pair at 128kpbs and up to eight Permanent Virtual Connections (PVCs) per access link.

The primary components of 2-Wire FRS are:

  • Access Link - Connection facility for the end-user's network interface to the corresponding CenturyLink Frame Relay Port at the speed of 128kbps.
  • User-To-Network Information Transfer (UNIT) - Transfers information between the User- to-Network Interface (UNI) and the ACS Frame Relay service network. The UNIT includes the associated port, unidirectional Permanent Virtual Connections (PVCs), and ACS Frame Relay switching equipment. It provides unidirectional polling between your end-user's facility and the ACS FRS network. It is the physical entry point into ACS Network.
  • Permanent Virtual Connection (PVC) - A unidirectional logical channel from one Frame Relay port to another Frame Relay port within the ACS network. PVCs are provisioned at end-user customer-selected port speeds with end-user customer-selected Committed Information Rates (CIRs). There is a limitation of 8 PVCs per access link.


2-Wire FRS is available in designated wire centers and only in some of CenturyLink QC. To check for availability by state, refer to the state specific tariffs/catalogs/price lists. To check for central office equipment availability, refer to the Network Disclosure web page.

Terms and Conditions

2-Wire FRS requires a contract number, even if the service is on a month-to-month basis. Please work with your CenturyLink Sales Executive to obtain this number.

Product limitations include:

  • No backhauling
  • Cannot be used as a Stand-alone Access Link
  • No Network-to-Network Information (NNI)
  • Not available via a Private Line Transport
  • All rules for Fractional Frame Relay Service will apply
  • Each access link can have a maximum of 8 PVCs
  • Service in only a 2-wire copper twisted pair
  • Data Link Connection Identifiers (DLCIs) are assigned in the 16 to 23 range

Technical Publications

Design requirements are specified in Technical Publication 77372.


Rate Structure

2-Wire FRS is generally billed for on a month-to-month basis or under a rate plan. Rate plans are available per the state specific tariffs/catalogs/price lists and may qualify for the resale discount. Contact your CenturyLink Sales Executive for additional billing information.

The three rate categories for 2-Wire FRS are:

  1. Access Link - Monthly and non-recurring charges apply
  2. UNIT - Monthly and non-recurring charges apply
  3. PVC - Non-recurring charges apply with a first and subsequent (additional) charge

Additional rate elements may apply for miscellaneous service order request items such as:

  • Due Date change charge
  • Cancellation charge
  • Change to a rate plan
  • Subsequent Changes

CenturyLink retail rates, rate elements, and how they apply for 2-Wire FRS service can be found in the state specific tariffs/catalogs/price lists.

Additional general resale rate structure information is located in the Resale General Overview.


Retail prices can be found in the state specific tariffs/catalogs/price lists.

CenturyLink's retail rates for 2-Wire FRS less any applicable resale discount, apply to resold 2-Wire FRS. Resale discounts can be found in the SGAT, Exhibit A for the relevant state.

If you have an existing Interconnection and/or Resale agreement with CenturyLink, resale discounts are included in your agreement.

Tariffs, Regulations and Policy

For terms and conditions applicable to CenturyLink retail products available for resale, view the state specific tariffs/catalogs/price lists.

Additional policy information can be found in the:

  • Interconnection agreement
  • Resale agreement
  • SGAT for the relevant state.

Optional Features

Customer Network Management (CNM) is a feature that provides your end-user with read-only access to information related to service faults, usage and Frame Relay service configurations. CNM includes a PVC which is dedicated to the feature and does not include the PVCs available to your end-user on a per port basis.


2-Wire Frame Relay Service can benefit your end-user in the following ways:

  • Interconnect Local Area Networks (LANs), allowing users at remote sites to appear as if they were on the network.
  • Connect with others on the network to communicate easily with customers, suppliers, consultants and others in the community of interest.
  • Compatible with most of your end-user's customer-owned ISDN equipment
  • No need to order or pay for a T-1


Applications for 2-Wire FRS include:

  • LAN traffic
  • High-speed mainframe connections
  • Large file transfer
  • Text imaging and forms processing
  • E-mail messaging
  • Point-of-Sale (POS) authorization
  • Packetized video
  • Switched access for remote and mobile users
  • Client-server applications, including distributed database access



If you are a new CLEC and are ready to enter the Interconnection business with CenturyLink, please view the Getting Started for Facility-Based CLECs or the Getting Started for Resellers web pages.

If you are an existing CLEC wishing to amend your Interconnection Agreement, you can find additional information in the Interconnection Agreement.

For 2-Wire FRS pricing plans, you must work with your CenturyLink Sales Executive to establish the contract and obtain a contract identification number. The contract identification number must be noted in the Variable Term Agreement (VTA) field of the Local Service Request (LSR) request.


The following functions may need to be performed by you in preparation for the issuance of an LSR:

  • Customer Service Record (CSR) retrieval and review
  • Address validation
  • Facility and Service availability validation
  • Connecting Facility Assignment (CFA) validation
  • Determine NC/NCI codes, number of PVCs to request, FR cloud information and CIR requested

CSRs for 2-Wire FRS can be retrieved either by placing a telephone call/fax to the CenturyLink Wholesale Customer Service Operation Center.

When contacting the center, please be prepared to provide them with the account telephone number, proof of agency authorization, and your fax number. CenturyLink will then fax the 2-Wire FRS CSR to you.


General ordering activities are identified in the Ordering Overview.

Service interval guidelines are found in the Service Interval Guide (SIG).

Resale 2-Wire FRS orders are placed via LSRs. Using REQTYP 'LB', Resale 2-Wire FRS will utilize the following forms:

  • Local Service Request (LSR)
  • End User Information (EU)
  • Resale Frame Relay (RFR)

Orders should be placed via the EASE-LSR GUI or EASE-LSR Extensible Markup Language (XML).

USOCs and FIDs for 2-Wire FRS can be found in the USOC and FID Find database.


General provisioning activities can be found in the Provisioning and Installation Overview.

Provisioning information relative to product design, performance and acceptance testing can be found in one or all of the following publications:

Firm Order Confirmation (FOC) intervals are found in the Service Interval Guide (SIG).

A jeopardy occurs on an LSR order if a condition exists that threatens timely completion. Jeopardy codes are described in the Provisioning and Installation Overview.

A Design Layout Report (DLR) will be provided when requested on the LSR. Information describing DLR viewing options is available in the Provisioning and Installation Overview.

Maintenance and Repair

CenturyLink will provide repair and maintenance of resold 2-Wire FRS in a manner that is equal to that which it provides to its retail end-users purchasing use of 2-Wire FRS. Additional information is available in the Maintenance and Repair Overview.


On a monthly basis, CenturyLink will provide you with billing information that will provide summary account information as well as end-user sub-account information. Detailed information regarding the CABS Summary Bill, Inquiry and Disputes is described in Billing Information Carrier Access Billing System (CABS).


Local CenturyLink 101 "Doing Business With CenturyLink"

  • This introductory web-based training course is designed to teach the Local CLEC and Local Reseller how to do business with CenturyLink. It will provide a general overview of products and services, CenturyLink billing and support systems, processes for submitting service requests, reports, and web resource access information. Click here to learn more about this course and to register.

Frame Relay Service - In Region

View additional CenturyLink courses in the Course Catalog.


General contact information is identified in the CLEC & Reseller Center Contacts web page.

Frequently Asked Questions (FAQs)

1. Is 2-Wire FRS available in subtending Frame Relay Service Offices?
2-Wire FRS is available in numerous offices but not in all. For availability be sure to conduct a facility and service availability validation and check Network Disclosure web page.

2. Can 2-Wire FRS be used for both voice and data traffic?
No, the 128kbps access link is a dedicated circuit that terminates on a D4 Channel Bank and connects to the FR switch. It does not connect to the voice switching network and therefore will not carry voice.

3. Is Message Service Delivery available on 2-Wire FRS?

4. Will I be able to obtain Frame Relay reports on my 2-Wire FRS?
No, the 2-Wire FRS access link is aggregated on an unchannelized T-1. This makes your performance data non-distinguishable from other 2-Wire FRS traffic riding the same unchannelized T-1.

5. If my end-user upgrades their service from a 56kbps to a 2-Wire FRS, can the CenturyLink network reuse the existing 56kbps facility for the 2-Wire FRS?
If the end-users 56kbps loop qualifies for 2-Wire FRS, then technically the facility can be re-used; however, CenturyLink would recommend that a new 2-Wire FRS circuit be installed first and then disconnect the existing 56kbps circuit to ensure your end-user does not experience any down time.

6. Are NNIs available with 2-Wire FRS?
No, however, when 2-Wire FRS comes out of the back end of the Channel Bank and goes into the unchannelized T-1 to the FRS switch and enters the FRS network, NNIs are then available as part of the normal 4-wire FRS.

Last Update: October 4, 2023

Last Reviewed: October 26, 2023