Wholesale: Products & Services

Billing Information - Daily Usage File (DUF) - V20.0

History Log


Some CenturyLink™ products generate usage records or call detail that is recorded at a CenturyLink Central Office Switch. This recorded usage is subsequently processed within the Ensemble billing system and, if identified as belonging to you, is packaged into a file, the Daily Usage File (DUF). The DUF is transmitted to you on a daily, weekly or monthly basis depending on what you requested in the New Customer Questionnaire. CenturyLink bills usage records based on applicable tariff, Interconnection Agreement, and/or Commercial Agreements applying the rated usage to your bill.  Products that generate recorded usage records can include, but are not limited to the following:

  • Business and Residence Exchange Lines
  • Centrex
  • Private Branch Exchange (PBX) Service
  • Public Access Line (PAL)
  • Single Line Integrated Services Digital Network/Basic Rate Interface (ISDN BRI)
  • Commercial local exchange services products, e.g. CenturyLink™ Local Services Platform (CLSP)

Click here for more specific information on these products.


The DUF is available upon request in the CenturyLink QC.

Terms and Conditions

To receive a DUF, CenturyLink must be the underlying network provider for local service.


DUF records can be for toll, access and local usage. These charges apply only to the wholesale channel, which are designated as RSID/ZCID accounts.

The rate to be charged per record will differ by state. Please refer to your Interconnection Agreement for specific rates.



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, you can find additional information in the Interconnection Agreement.

The DUF can be transmitted in three different media types to you. You will choose the method of transmission when completing the New Customer Questionnaire. Once the questionnaire is completed and submitted, a technical review of the questionnaire will be done by a representative from the CenturyLink Information Technology (IT) Wholesale Systems Implementation and Deployment Team. This representative will schedule a meeting with you to assist with any technical questions regarding the DUF.

The media types are:

  • Network Data Mover (NDM) (Dedicated Circuit)
  • File Transfer Protocol (FTP) - (Direct Only) (Dedicated Circuit)
  • File Transfer Protocol Secure (FTPS) – (Direct Only) (Dedicated Circuit)
  • Web Access

The New Customer Questionnaire requires you to provide the following information concerning the Daily Usage Output:

  • Contact Name
  • Contact Telephone Number
  • Mailing Name
  • Mailing Address
  • Type of Service
  • Electronic Transfer Options
    • NDM (Dedicated circuit)
    • FTP or FTPS (Dedicated Circuit)
      • Circuit ID
      • Transmission Path/Nodes
    • WEB
      • Provide name, telephone number and CUID for person who will access the data via the WEB, if different than the technical contact listed
  • Data Set Name (DSN)/Remote ID
  • Record Length Options
  • Technical Contact
  • Technical Contact Telephone Number

NOTE: If you wish to change your DUF media type after you are established, it will be necessary for you to resubmit a New Customer Questionnaire advising of the requested media change. The questionnaire is submitted per the procedures outlined on the questionnaire.

Click here for more information on the New Customer Questionnaire.

DUF Record Format
The DUF is sent to you in Ordering and Billing Forum (OBF) Exchange Message Interface (EMI) format. Recorded call information, will conform to EMI guidelines for each applicable recorded usage record and record type. Applicable usage records are dependent on the Class of Service for each account. For example, a Measured Class of Service includes all local usage records, but a Flat Class of Service does not include local usage. In order for you to be able to read and understand the record layout, you must order the EMI Documentation (SR 320) prepared by OBF.

Types of Records in DUF
Once you become the provider of record on a line, CenturyLink will report to you, as appropriate and applicable, all usage associated with that line, including local, intraLATA (Local Access and Transport Area) and switched access. Examples of some recorded usage records you will receive on the DUF are Directory Assistance (DA), Local Measured Service (LMS), usage sensitive CLASSTM features CenturyLink provided intraLATA toll and, if applicable, originating and terminating switched access records.

DUF Processing
Recorded usage records are processed daily and posted to internal toll guides generated by service order activity within CenturyLink’s billing systems. Toll guides are also used to identify the Competitive Local Exchange Carrier (CLEC) who is to receive the recorded usage sent on the DUF. Additionally, recent service order activity is checked prior to sending records to the DUF to ensure usage is processed correctly.

Reseller DUF
If you establish as a Reseller you will only receive recorded usage (non access) records on your DUF. The DUF file itself will be generated and delivered in the format requested by you in the New Customer Questionnaire. The recorded usage records within each DUF file are sorted internally by the originating numbers Regional Account Office (RAO), creating multiple "packs" of recorded usage records in each DUF. For example, all recorded usage records in RAO 153 are packed together with a header/trailer while all recorded usage records in RAO 062 are packed together with a different header/trailer, but both of these "packs" appear in the single DUF file.

If you are established as a UNE provider, you will receive not only recorded usage records but also originating and terminating switched access records on your DUF. All switched access records are "packed" into a single file with only one header/trailer. Unless otherwise specified, you will receive both recorded usage records and switched access records on the same DUF file (parsed internally by specific EMI header/trailer records). As a UNE provider you also have the option of splitting your DUF file by separating the recorded usage records into one file (commonly referred to as the ODUF) and the switched access records into another file (commonly referred to as the ADUF). Information supplied by you on the New Customer Questionnaire identifies which method is selected to receive your DUF file(s).

DUF Transmission Days
Normally, you will receive the DUF daily (Monday through Friday, excluding CenturyLink holidays). If there is no usage recorded on a particular day, you will not receive a file or any notice from CenturyLink that usage was not recorded, and a file will not be sent.

The following table shows, by state, the transmission schedules available to you:

State Daily Weekly Monthly
Arizona X X X
Colorado X X X
Iowa X X X
Minnesota X X X
Montana X X X
Nebraska X X X
North Dakota X X X
New Mexico X X X
Northern Idaho X X X
Oregon X X X
South Dakota X X X
Southern Idaho X X X
Utah X X X
Washington X X X

Types of Records:
The DUF file may include both rated and unrated usage as well as access records.

Depending upon the type of call made, the DUF can include, but is not limited to, the following types of rated or unrated usage records and/or access records:

  • Residence and Business Measured Service Usage
  • 8XX and 900 Access Records
  • 8XX Service Line and Wide Area Telephone Service (WATS) Usage
  • IntraLATA Toll
  • Continuous Redial
  • Call Trace
  • Directory Assistance (DA)
  • Directory Assistance Complete A Call (DACC)
  • Switched Access (UNE products)

The following is a list of common EMI record types generated by CenturyLink:

  • Detail Records (rated local and toll messages) - 010101, 010104, 010105, 010116, 010118, 010119, 010125, 010131, 010132, 010135, 010137
  • Detail Records (unrated local and toll messages) - 100101, 100116, 100118, 100119, 100131, 100132, 100137
  • Detail Records (Switched Access) - 110101, 110201, 110125, 110105
  • Credit Records - 0301XX
  • Rated Credit Records - 4101XX

(Note: Any valid local or toll EMI record type originating from other CLECs or Independent Local Exchange Carriers (ILEC) can be passed on the DUF):

Rated Usage
Rated Usage records are usage records that CenturyLink receives from other CLECs and ILECs.

Unrated Usage
CenturyLink usage recorded at a CenturyLink Central Office (CO) switch comprises a majority of the usage appearing on the DUF. This recorded usage is subsequently processed within the CRIS billing system and once identified as belonging to a CLEC, is packaged into the DUF. Some examples of unrated usage are:

  • IntraLATA Toll
  • Continuous Redial
  • Call Trace
  • Directory Assistance (DA)
  • Directory Assistance Complete A Call (DACC)
  • Local Measured Service

NOTE: The DUF will not contain usage records coming from an Interexchange Carrier (IXC) for your end-user billing. Any usage records CenturyLink receives from an IXC that involve a CLECs end-user will be returned to the IXC per industry guidelines.

Any usage questions should be referred to you CenturyLink Billing Service Delivery Coordinator (SDC).

If you need to return DUF records to CenturyLink, you may do so for any number of reasons, among which are:

  • Incomplete Records - Not all elements provided
  • Invalid Fields
  • Unreadable Records
  • Record has been Misdirected - directed to incorrect account
  • Duplicated Records
  • Damaged Information

Records are sent to you in packs that are groups of messages with a header and trailer. If the pack errors, the return of the pack is handled over the same circuit that was used to transmit the DUF to you.

You can also return to CenturyLink record level errors, which are individual records within a pack. In order for you to return these record level errors mechanically, you must subscribe to the Co-Carrier Usage Return (CCUR) system.

To subscribe to CCUR, complete the section of the New Customer Questionnaire regarding CLEC Usage Return. The information included in this section is:

  • Contact Name and Number
  • Type of Service
  • Electronic Transfer Option
  • Record Length
  • Technical Contact and Number

When records are returned, you must also provide return reason or error codes that explain why the records are being returned. You must return any usage errors within 90 days. Return reasons and/or error codes can be found in the EMI documentation produced by OBF.

Complete requirements and other required information will be provided to the CLEC at the time they subscribe to CCUR.

When usage is returned to CenturyLink, the CCUR system will attempt to re-guide (re-direct) the records for up to three business days. During that time, various results are possible including the following:

Usage record found to be correct

  • Usage record is returned to you on the returned CCUR file. The record is considered to be "Correct as written"

CCUR rejects the record

  • The CCUR may reject the record for several reasons, including but not limited to:
    • Duplication of Record(s) Previously Returned
    • Records older than 90 days from the date of the erred record
    • Invalid or No Return Code

CCUR re-guides the record

  • When records are returned because the CLEC is unable to identify the billing account number, CCUR will attempt to determine or verify the correct billing number and will generate a report with the correct billing number details. This report is used by the CenturyLink SDC to have the account corrected within the guiding system so usage can be sent to the correct CLEC. The Billing SDC will notify the returning CLEC of any adjustments that have been made to their billing account. The Billing SDC must respond to you within two weeks of the bill date on which the usage appeared.

CCUR is unable to correct the record(s)

  • CCUR generates a report with the message details. CenturyLink uses this report when the bill for that usage record(s) has been generated. CenturyLink may then initiate a Billing Error Adjustment on your billing account. CenturyLink will notify you of any adjustments that have been made. The Billing SDC must respond to you within two weeks of the bill date on which the usage appeared.

Maintenance and Repair

If you need a retransmission of the DUF, you should contact the Wholesale Systems Help Desk and be prepared to give the following information:

  • Date of Original Transmission
  • Media Type
  • Dataset Name (if Connect:Direct/NDM output)
  • Identification Number (RSID/ZCID)
  • Contact Name and Number

Usage Data is stored for 180 days at CenturyLink. After that time, retransmission is not possible and a request for retransmission will be denied.


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 Training.

View additional CenturyLink courses by clicking on Training Catalog.


CenturyLink contact information is located in Wholesale Customer Contacts.

Frequently Asked Questions (FAQs)

1. How can I correctly read and understand the DUF?
The DUF is in EMI Format, which is an industry guideline.

2. What is on the DUF?
The DUF contains rated and unrated call detail records and, if applicable, access records.

3. How is the DUF sorted?
The DUF is sorted by the "from" RAO.

4. When does CenturyLink require a local node for NDM Access?
CenturyLink needs you to supply your local node in order to receive files via NDM.

5. How do I get set up to receive a DUF?
This is accomplished by completing the New Customer Questionnaire.

6. How do I subscribe to CCUR?
This is accomplished by completing the New Customer Questionnaire.

Last Update: January 31, 2024

Last Reviewed: March 18, 2024