Wholesale: Products & Services

Digital Data Service (DDS) - V6.0

History Log

Product Description

Digital Data Service (DDS) is a Private Line channel with the capability of transmitting digital data over a dedicated point-to-point or multipoint circuit. The available data rates are 2.4, 4.8, 9.6, 19.2, 56.0 and 64.0 Kilobits per second (Kbps).

The service provides full-duplex, four-wire transmission of synchronous serial data between two end users or between an end user and another carrier. CenturyLink™ provides timing for this service through facilities to the end user on the received bit stream. DDS is available only between locations connectable through compatible digital facilities.

Note: DDS is a private line (dedicated) digital service and is not a switched service; therefore, no dial up can occur.

Digital Data Service (DDS) is offered as a two-point or multipoint service:

  • A two-point channel connects between two customer locations or, in the case of the COMMAND-A-LINK™, between a customer location and a CenturyLink Central Office
  • Multipoint (Bridging) is a bridging arrangement for multipoint circuits. It is available only at selected offices identified in Federal Communications Commission (FCC) No. 4 National Exchange Carrier Association tariff as a "DDS Hub." Additional bridging locations are available in some states (for intrastate applications only) in offices identified as "DDS” Nodes." Multipoint circuits are used to connect three or more stations together into a single DDS circuit. The circuits consist of a single master or control leg and two or more remote legs. The legs are connected together in a DDS Hub by a bridge. Each leg is identified and designed separately. The figure below--Figure 1, "Three Station Multipoint Circuit," illustrates a three-leg (i.e., a three-station) multipoint circuit. The Customer Provided Equipment (CPE) connected to the control leg controls the circuit. The bridge broadcasts the information transmitted by the control station to all remote legs. The control station maintains protocol so that the proper remote station recognizes the incoming information as being for that station. The bridge adds together all information coming upstream from the remote stations and passes the resulting signal on to the master station. The master station's protocol ensures that only one remote station is talking at a time to avoid garble.

Product Diagram No. 1

Product Diagram No. 2


Digital Data Service is available where facilities exist throughout CenturyLink QC.

Digital Data Service can be purchased on an Intrastate or an Interstate basis. Digital Data Service (DDS) can be provisioned through multiple CenturyLink wire centers.

Terms and Conditions

Terms and Conditions section does not apply to Digital Data Service

Technical Publications

Technical characteristics, including Network Channel/Network Channel Interface (NC/NCI™) codes, are described in Technical Publication, CenturyLink Digital Data Service Technical Description, 77312 or Technical Publication, CenturyLink Digital Data Service Product Description, Applications and Interface Combination, 77204


Rate Structure

Recurring charges are comprised of the following rate elements depending on jurisdiction:

  • Channel Termination or Network Access Channel (NAC) and Channel Performance
  • Transport Mileage, if applicable
  • Optional Features

Nonrecurring charges are comprise of the following rate elements depending on jurisdiction:

  • Channel Termination
  • Channel Performance
  • Optional Features
  • Transport Mileage, if applicable
  • Service Provisioning

For Interstate pricing see CenturyLink Operating Companies Tariff F.C.C. No. 11 or for Intrastate see Private Line state specific tariff.

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

Optional Features

  • Secondary Channel provides an independent lower-data rate channel that the customer may use to control or monitor its own network. The specific application is dependent on the customer-owned Channel Service Unit/Data Service Unit (CSU/DSU). This option is available at the 2.4 through 56.0 Kbit/s data rates. See Technical Publication, CenturyLink Digital Data Service Technical Description, 77312 or ANSI T1.410-1992, "Carrier-to-Customer Metallic Interface--Digital Data at 64 Kbit/s and Subrates," for further information.
  • Transfer Arrangement option allows a customer to transfer a leg of a CenturyLink Digital Data Service (DDS) circuit to another channel that terminates in either the same or in a different customer designated premises. A key activated control channel operates the Transfer Arrangement. The customer must order a Low-Speed Data Channel service between the customer's key location and the Transfer Arrangement located in the CenturyLink Central Office. The transfer arrangement is available only in the Interstate Access jurisdiction.
  • COMMAND A LINKSM allows the customer to control the reconfiguration of a network consisting of CenturyLink Digital Data Service circuits on a near real-time basis. The reconfiguration is done by using an Intelligent Network Element, such as a Digital Cross-connect System (DCS). The circuits purchased to work with COMMAND A LINKSM go from a customer location to the COMMAND A LINKSM device located in a CenturyLink Central Office. This service is available only at selected locations. See Technical Publication 77371, COMMAND A LINKSM Technical Description And Interface Combinations, 77371
  • Direct Digital Access Line (DDAL) Public Switched Digital Service (PSDS) is a switched-service offering that provides the customer with the capability of establishing (by way of a PSDS network) a 56 Kbit/s digital circuit. This option provides a 56 Kbit/s access channel with the added capability of carrying signaling for a PSDS circuit. A DDAL line may also be used with a private switched digital network. The switch will not be provided by CenturyLink with DDAL. The document, ANSI/TIA/EIA 596-1992, "Network Channel Terminating Equipment for Public Switched Digital Service," describes the PSDS service. The ANSI document identifies the DDAL option as "Type I." Customers needing information about a specific PSDS service should contact their PSDS service provider.
  • Bridging
  • Central Office Multiplexing
  • Central Office Mulitplexer to Multiplexer Connecting Arrangement

Optional features for DDS are described in Technical Publication, CenturyLink Digital Data Service Technical Description, 77312 or Technical Publication, CenturyLink Digital Data Service Product Description, Applications and Interface Combination, 77204.


Features Benefits
  • 24 hour 7 day a week
  • Ubiquitous
  • DDS is available in CenturyLink local serving areas in AZ, CO, IA ,ID ,MN ,MT ,ND, NE, NM, OR ,SD, UT, WA, WY
  • Responsiveness
  • Service and repair guarantees are offered on DS3 service, for details see Tariffs/Catalogs/Price Lists.
  • Provides connection with other digital services
  • DS1, DS3, Frame Relay (FR), Simultaneous Voice & Data Service (SVDS), Synchronous Service Transport (SST), Self-Healing Network Service (SHNS).
  • Applications



    Product Prerequisites

    If you are an Interexchange Carrier (IXC), Internet & Data (ISP) or Wireless Service Provider (WSP) and have questions regarding your contract with CenturyLink, contact your Account Team / Sales Executives and Service Managers for more information.


    Pre-Ordering section does not apply to Digital Data Service


    DDS service requests are submitted using the following Access Service Ordering Guidelines (ASOG) forms:

    • Access Service Request
    • Administrative
    • Transport Request
    • Service Address Location Information Form
    • Multipoint Service Leg

    Field entry requirements are described in the Access Service Request (ASR) Forms.

    A Design Layout Record (DLR) request is requested through the ASR service order process.

    Contact your Account Team / Sales Executives and Service Managers for more information.

    Provisioning and Installation

    FOC intervals are found in the Service Interval Guide (SIG) for Access Services.

    Maintenance and Repair

    Maintenance and repair problems are reported to the CenturyLink Customer Service Center 1-800-954-1211. If your end-users experience problems with their local circuits or services, provisioned with CenturyLink provided products and services, their first point of contact is you, their local service provider. You or your end-user must isolate the trouble and verify it is not the customer-owned equipment or cable before calling.


    Carrier Access Billing System (CABS) billing is described in Billing Information - Carrier Access Billing System (CABS). .


    Digital Data Service (DDS)

    View additional CenturyLink courses by clicking on Course Catalog.


    Contact your CenturyLink contact information is located in Wholesale Customer Contacts.

    Frequently Asked Questions (FAQs)

    1. What type of Consumer Premise Equipment (CPE) is required?
    A Channel Service Unit/Data Service Unit (CSU/DSU) is required at the customer's premise that enables digital transmissions to occur at a 2.4, 4.8, 9.6, 19.2, 56, or 64 KBPS rate. The CSU/DSU is generally connected to a business/government host computer Local Area Network (LAN) for secure digital access.

    2. Can Digital Data Service be connected to other services?
    Yes, including Private Line DS1, DS3, OC-n services through "Multiplexers", sometimes called "muxes". DDS can also be connected to Frame Relay networks.

    3. When is "bridging" utilized with a Digital Data Service network?
    Bridging can be done at designated CenturyLink Digital Data Service wire centers referred to as "DDS Hubs" locations. All DDS speeds except 64 KBPS can be bridged together at the customer designated "DDS Hub" locations identified in the FCC NECA #4 tariff. Currently, very efficient, cost effective, and secure DDS bridged networks are being utilized by business and government customers through out our service areas.

    4. Is their discount pricing for Digital Data Service?
    Yes, DDS can be ordered monthly, 36 month, or 60 months. The 36 and 60-month plans offer very attractive discounts when compared to monthly service. Contact your CenturyLink Account Team Representative for further information.

    5. Can upgrades in service be made for Digital Data Service?
    Yes, most Private Line Solutions products offer upgrades including DDS. The most frequent upgrades are to higher DDS speeds (i.e., 56 Kbps/64 KBPS) or DS1 (1.544 MBPS) service.

    Last Update: January 30, 2017

    NC/NCI™ is a trademark of Telecordia Technologies Inc.
    COMMAND A LINKSM is a Service Mark of CenturyLink™