Wholesale: Products & Services

Resale - Integrated T-1 (IT1) V11.0

History Log

Product Description

CenturyLink's retail telecommunication service, Integrated T-1 (IT1) 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 Resale General Product Catalog (PCAT).

IT1 service provides a two-point digital intrastate/intraLATA 1.544 Mbps private line facility from your end-user's premises to the CenturyLink serving wire center. IT1 includes the Digital Signal Level 1(DS1) facility, common equipment, local switching, and twenty-four flat rated channels for access to the local exchange and toll network. Your end-user can channelize the DS1 into twenty-four channels using their Customer Provided Equipment (CPE). Your end-user's CPE can include a Private Branch Exchange (PBX), D4 type channel bank, Coder/Decoder (CODEC) equipment or router and must be compatible with IT1 service.

You will need to specify on your requests the number of voice and data channels required for different services (e.g., Advanced Voice Channel, Basic Voice Channel, etc). These channels can be utilized for different services at your end—user's discretion. The following are the available channel types:

  • Advanced Voice Channel - Channels that terminate on the trunk unit of a CenturyLink switch and should be ordered if the end-user equipment requires trunk side features such as Direct Inward Dial (DID), Direct Outward Dial (DOD) with Answer Supervision, or 2-way DID with Answer Supervision.
  • Basic Voice Channel - Channels that terminate on the line unit of a CenturyLink switch using a multiplexer. Your end-user's CPE derives the twenty-four 64 Kbps channels within the IT1. This service should be ordered if your end-user 's equipment requires line-side features such as Caller ID. The channel can be designed as:
    • In-only - Traffic transmitted from the central office to the CPE
    • Out-only - Traffic transmitted from the CPE to the central office
    • 2-way - Traffic transmitted from either the central office or the CPE.
  • Basic Integrated Services Digital Network (ISDN) 2B+D (Single Line Service (SLS)) - Utilizes three consecutive DS0 channels on the IT1 to provide two primary 64 kbps or B (Bearer) channels that can be used simultaneously and independently to carry any combination of voice, data, image or video calls. It provides a third secondary 16 kbps or D (Delta) channel for low to moderate speed data communications.
  • Basic Dedicated Digital Data Channel - Channels with the capability of transmitting digital data. The data rate is 56 or 64 kbps. It is available between locations connectable through compatible digital facilities. The data rate of 64 kbps may not be available in all jurisdictions.
  • Frame Relay Dedicated Digital Data Channel - Employs "fast-packet" technology with access speed of 56 kbps and 64 kbps to provide high-speed connection oriented data transfer service. This service is useful for applications such as Local Area Network (LAN) and file transfer that include short bursts of data with variable bandwidth.


IT1 service is available where facilities exist throughout CenturyLink QC.

Terms and Conditions

IT1 is subject to the availability of central office (CO) facilities.

CenturyLink will determine the type of facility and common equipment (Digital Cross-connect System (DCS) or D4 channel banks) that it will use for the service. A fiber optic facility may be engineered if you specifically request it.

When 800 service lines terminate on an IT1 facility, the 800 service access lines are classified as basic voice channels for the application of the IT1 facility and common equipment rate and charges. Rates and charges for 800 service also apply.

You must ensure that your end-user provides multiplexing/de-multiplexing capabilities at their premises for channels riding the IT1 facility. You will be responsible for channel assignment on the IT1 facility.

IT1 service is:

  • Available on an intrastate/intraLATA basis only
  • Allowed to ride an existing Digital Service Level 3 (DS3) facility.

IT1 service is not available for use by Commercial Mobile Radio Carriers (CMRS), Private Mobile Radio Carrier (PMRS), or Inter-exchange Carriers in the provision of services to their customers. Therefore, the following services are not allowed to traverse a resale IT1 facility:

  • Access lines and PBX trunks that are not ordered under the IT1 umbrella
  • Caller ID Trunk Side (Advanced Trunk)
  • Identified Outward Dialing (IOD)
  • Feature Groups A, B, C or D
  • Other private line/access services and facilities unless otherwise specified
  • Basic exchange enhancement
  • Joint user service in some states
  • Wire maintenance plans
  • SWITCHNET 56 Service
  • Hotel/Hospital Semipublic Service
  • CMRS and PMRS (Commercial Carriers).

Where appropriate for services provisioned on the IT1 facility:

  • You must provide CenturyLink with accurate end-user location information for state regulated emergency reasons. Guidelines to update information for the E911 system are located in the emergency 911/E911 PCAT.
  • CenturyLink will accept one white page directory listing for each main telephone number at no charge. Additional information about directory listings is available in the White Pages Directory Listings PCAT.

Technical Publications

Product technical publications are specified in the following documents:


Rate Structure

Unless otherwise negotiated, IT1 service is billed on a rate-stabilization pricing (RSP) plan per the state specific tariffs/catalogs/price lists and may qualify for the resale discount. Penalties for early termination of the plan may apply.

Contact your CenturyLink Sales Executive for additional billing information.

Charges for Resale IT1 will apply to the IT1 facility, to features/services of the facility, and to features/services on the channels that ride the facility.

Monthly recurring and non-recurring charges apply to the facility service order. The rates will vary based on the terms of the agreement (e.g., 1 year, 3 years, or 5 years).

Monthly recurring and non-recurring charges may apply to the following rate elements of the channel service orders. Detailed information for these charges may be found in each of the product-specific PCATs.

  • DID Termination
  • DID Station Numbers
  • Call Transfer
  • Hunting
  • Frame Relay Port
  • Frame Relay PVC
  • Channel Performance.

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

  • Reconfigure the IT1 facility
  • Change or rearrange each IT1 trunk
  • Change or terminate a rate plan.

CenturyLink retail rates and rate elements, and how they apply for IT1 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.


Rates and/or applicable discounts are available in Exhibit A or the specific rate sheet in your Interconnection or Resale Agreement.

Tariffs, Regulations and Policy

Tariffs, regulations and policies are located in the state specific Tariffs/Catalogs/Price Lists.

Additional policy information can be found in your Interconnection Agreement, Resale Agreement, or in the SGAT for the relevant state.

Optional Features

Optional features associated with the IT1 facility include:

  • CO Multiplexing
  • Clear Channel Capability
  • Extended Superframe
  • Customer Controlled Reconfiguration
  • Synchronization.

Additional details addressing these features and their design requirements are found in the 1.544 Mbps Channel Interfaces Technical Publication 77375.

Optional features for the product lines ISDN-Basic Rate Interface (BRI), Frame Relay and PBX service are available, provided they are compatible with the user's CPE. Details for these options can be found in their respective PCATs.


Benefits of an IT1 service include:

  • Reduces costs
  • Improves dependability of dial-up data transmissions
  • Consolidates trunks onto a DS1 interface
  • Provides precision timing for call accounting software
  • Improves voice and data transmission.


IT1 offers many benefits to your end-user who:

  • Currently owns a digital PBX
  • Plans to purchase a new digital PBX or grow their existing PBX
  • Wants to save capital expense up front on the purchase of a new PBX
  • Wants the reliability of a low error rate of digital transmission
  • Wants precision timing for call accounting software
  • Uses dial-up data
  • Requires 56 or 64 Kb/s transmission
  • Wants to update to current technology
  • Needs a reduced loss level on trunks
  • Needs Digital Data Service in addition to voice channels
  • Wants CenturyLink's 800 Service to be used with IT1
  • Wants Fractional Frame Relay
  • Wants to aggregate DS0
  • Wants a variety of services on one DS1 pipe at a reduced cost.


Product Prerequisites

If you are a new CLEC and are ready to do business with CenturyLink, please view Getting Started as a Facility-Based CLEC or Getting Started as a Reseller.

If you are an existing CLEC wishing to amend your Interconnection Agreement or your New Customer Questionnaire, additional information is located in the Interconnection Agreement.

For term pricing plans, please 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) form.


General pre-ordering activities are located in the Pre-Ordering Overview.

To verify if a DS1 (T1) is available to provision IT1, use the EASE-LSR User's Guide. Follow the instructions for a High-Capacity Facility check. In completing the High-Capacity Facility check, use the Class of Service and USOC specific to the product for which you are checking the facility. If the DS1 is riding a higher facility (DS3), a facility check is not performed.

Or if you use Extensible Markup Language (XML), select the release you would like to use to execute the query and scroll to the chapter that is titled "Facility Availability Transaction" and follow the instructions.

CenturyLink strongly suggests that you complete this DS1 pre-order process in addition to verifying trunk availability in the CO. By checking trunk availability in the CO and the DS1 availability you will be able to determine that the service can be provisioned.

If facilities are not available, you may continue to place your request for Resale IT1 however your order may be delayed.

The following functions may need to be performed by you in preparation for the issuance of the local service request:

  • Validate Address
  • Check Facility Availability
  • Service Availability
  • Review Customer Service Record (CSR) for both the services riding the facility and the facility.

    There are at least two CSRs for each IT1 service configuration:

    • the T1 facility CSR
    • one or more trunk CSRs for the services riding the T1

    When converting these products, both the facility and the trunks are to be converted and you must review both the facility and the trunk CSRs. Based on the type of request, subsequent changes may also require the review of both CSRs.

    Because of the different types of services that can ride an IT1, the IT1 CSR retrieval process differs from the standard EASE-LSR process.

    If some of the services riding the T1 are Frame Relay Access Links (FRALs), contact the CenturyLink Wholesale Customer Service Operation Center. They can provide both the trunk and facility frame relay CSRs via fax. For additional information about Frame Relay Service (FRS), see the FRS product information.

    If the services riding the T1 are analog or digital private lines, the CSRs have a private line account number, also known as a Mechanized Account Number (MAN) or Special Billing Number (SBN). You can use the MAN/SBN of the private line to obtain the DS0/VG CSR in EASE-LSR, for example, MAN/SBN format: 206 T31-1234 123. For additional information about private lines, see the Private Line Transport DS0/VG product information.

    If the services riding the T1 are DSS or ISDN-BRI, the trunk CSR has a standard telephone number as the account telephone number and is available in EASE-LSR via the standard pre-order CSR request function.

    Regardless of the type of services riding it, the facility CSR has an MAN/SBN account number. If you know this account number, you can also obtain the facility CSR via EASE-LSR. If you don't have the account number, you may find it cross-referenced on the trunk CSR. The cross-reference may appear:

    • Following the COS (Customer Other Service) Field Identifier (FID) in the Bill Section e.g., COS 206-T31-1234
    • Following the DES (Description) FID or WW (Works With) FIDs after the trunk Universal Service Order Code (USOC) e.g., TD21X/TN 206-224-2222/WW 206-T31-1234.

    If the facility account number is not referenced on the trunk CSR, locate the Common Language Facility Identification (CLFI). The CLFI appears on the trunk after each trunk USOC, following the CFA (Connecting Facility Assignment) FID, and identifies the name of the facility the trunk rides, as well as the channel it occupies, e.g., CFA 101 T1ZF 23 CLLI CLLI. CenturyLink can use the CLFI to obtain the facility account number for you.

    For non-FRS related service, if you are unable to locate the facility CSR, call the Wholesale Customer Service Operation Center and select the Centrex and Complex Resale option to reach the appropriate workgroup.

    When contacting CenturyLink, be prepared to provide:

    • End user name
    • Trunk account number
    • CFA or CLFI information
    • Proof of agency authorization.

    Depending on your needs, CenturyLink can:

    • Give you the account number so you can find the CSR in EASE-LSR
    • Fax, mail, or e-mail the CSR to you
    • Review the CSR with you on the telephone.


It is important to understand the Resale General procedures before ordering Resale IT1.

Refer to the ISDN-PRI Resale Facility product type in the LSOG to determine your ordering requirements for the IT1 facility. For the services riding the T1 facility refer to their respective product guidelines.

To differentiate your request from ISDN service, be sure to note the following appropriate IT1 USOCs in the Remarks section of the RPL form.

  • Month-to-month: HET9N
  • 1 year term: EH1D1
  • 3 year term: EH1D2
  • 5 year term: EH1D3.

General ordering activities are identified in the Ordering Overview.

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

For new installations, two local service requests must be issued at the same time and related to each other by using the RPON field on the LSR forms. The Due Date on the facility request must be prior to the Due Date on the request for the services riding it.

New installation requests for the simultaneous ordering of both the facility and the services riding it are to be faxed (888) 796-9089. Once the facility has been established, subsequent requests may then be placed via the EASE-LSR - Graphical User Interface (EASE-LSR GUI) or EASE-LSR Mediated Access - Extensible Markup Language (XML).

Resale IT1 service requests are placed using Local Service Ordering Guidelines (LSOG) forms. Detailed information is available in the LSOG.

The following forms may be used:

To request services riding the facility

  • Local Service Request (LSR) - for switched and non-switched services
  • End-User (EU) - for switched services and for frame relay service
  • Resale Service (RS) - for switched services only
  • Resale Frame Relay (RFR) for frame relay - for non switched services only
  • Directory Listing, as appropriate (DL) - for switched services only

Facility request

  • Local Service Request (LSR)
  • Resale Private Line (RPL)

Screening Telephone Number (S2N)

A Screening Telephone number identified by the USOC S2N is required on all in-only and two-way DID trunk groups. The S2N USOC is associated with a telephone number that will be used for toll billing and emergency 911 identification. Multiple trunk groups can share the same S2N telephone number.

This number must be a dialable number that can be called back by emergency services personnel and will be answered by your end-user. Whenever possible, your end-user's published number should be used for the S2N. When this is not possible, CenturyLink will accept a DID number, another POTS or trunk number, or a stand-alone DID number assigned specifically for this use.

When working with existing service, you should review the CSR to see if an S2N telephone number is assigned for each trunk group that requires one. If the S2N telephone number does not appear on the CSR, you must negotiate with your end-user to determine which number is to be used. Provide the information to CenturyLink by populating "S2N" in the Feature field and the telephone number in the Feature Detail field of the RS form.

When requesting new service, you should negotiate with your end-user which S2N telephone number assignment option they prefer; published number, other number in a DID range, or stand-alone DID. Populate the USOC "S2N" in the Feature field of the RS form and the chosen option in REMARKS, for example, "Use published number for S2N."

CenturyLink will provide the assigned S2N telephone number on the FOC. It is your responsibility to communicate this telephone number to your end-user and/or their CPE vendor and ensure that they connect it to a telephone someone will answer when the number is called.

If all the services that ride the facility are to be disconnected, you must issue a related request to disconnect the facility as well.

For pricing plans, be sure to enter your contract identification number in the VTA field on the LSR form.

USOCs and Field Identifiers (FIDs) for IT1 service can be found in the USOC and FID Finder database. Select the Family Product List option for Digital Switched Services to obtain IT1 USOCs/FIDs grouped by product type. USOCs are also listed in the state specfic .

Provisioning and Installation

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

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

A jeopardy situation occurs on a LSR request, if a condition exists that threatens timely completion. Jeopardy notification is 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

IT1 includes both a facility and the accompanying channels. When placing trouble reports, the account telephone number and/or the appropriate circuit identification must be provided. Please provide information on both the facility and channels to ensure proper isolation of the problem.

General maintenance and repair activities are described 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 account information.

Customer Records and Information System (CRIS) billing is described in Billing Information - Customer Records and Information System (CRIS).


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 for Course detail and registration information.

PBX Trunks

  • This self-directed, product-training course provides the participant with knowledge of the CenturyLink PBX Trunk product. Participants will learn how PBX works and the options available. A DID overview and a description of DID features and functions are part of this training course. Please click here to learn more about this course and to register.

Digital Switched Service (DSS)

Digital Service-Level 1 (DS1)

Frame Relay Service - In Region

View additional CenturyLink courses in the Course Catalog.


CenturyLink contact information is located in Wholesale Customer Contacts.

Frequently Asked Questions (FAQs)

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Last Update:April 6, 2015

Last Reviewed: November 13, 2023