Wholesale: Products & Services

Switched Access Services Ė V2.0

Product Description

Switched Access Services, CenturyLink™'s most basic group of services, enables access customers, i.e., Interexchange Carriers (IXC), to complete end-user requests for intrastate or interstate long-distance calls.

Switched Access Service, which is available to customers for their use in furnishing their services to end users, provides a two-point electrical communications path between a customerís premises and an end userís premises. It provides for the use of terminating, switching, transport facilities and common subscriber plant of the Company. Switched Access Service provides for the ability to originate calls from an end userís premises to a customerís premises, and to terminate calls from a customerís premises to an end userís premises in the LATA where it is provided.

More detailed Switched Access information, including diagrams, can be found in the CenturyLink Operating Companies F.C.C.Tariff (F.C.C. No. 2, 3, 4, 6, 7, 8, 9), and applicable state tariffs.

How the Service is Offered

Switched Access Service is available in several different serving arrangements and technical characteristics, e.g., services for lineside or trunkside connections, as well as in different Feature Group arrangements.


Switched Access Service is available where facilities exist throughout CenturyLink territory.

Terms and Conditions

Terms and conditions for the ordering, billing and provisioning of Switched Access Services are contained in CenturyLink Operating Companies F.C.C.Tariff, and applicable state tariffs.

Technical Publications

Feature Group D

  • TR-NPL-000258- Compatibility information for Feature Group D Switched Access Service

Feature Group A

  • TR-NPL-000377 Ė Compatibility information for Feature Group A Switched Access Service

Feature Group B

  • GR-334 Ė Switched Access Service: Transmission Parameter Limits and Interface Combinations

More Information:


Rate Structure

The Switched Access Service rate structure is complex, and includes MOU (Minutes of Use) and flat recurring charges. Rates depend on the type of service requested.

Major rate categories for Switched Access Service:  
Switched Transport Month to Month
Local Switching  
Common Line (CL) Carrier Common Line


Further information about these rate categories can be obtained in the CenturyLink Operating Companies F.C.C.Tariff,

Summary of Rate Categories and Elements

Rate Element Explanation Type of charge
Rate Category:  Switched Transport
Entrance Facility (EF) Dedicated switched transport facility from carrier’s POP to CenturyLink Serving Wire Center (SWC) Monthly fixed rate, based on facility provided, e.g., DS0, DS1, or DS3
Direct Trunk Transport (DTT) Transport from the SWC of the customer’s premises to an end office on dedicated circuits, and from the SWC to the Access Tandem Monthly fixed rate, plus monthly per mile rate based on facility provided, e.g., DS0, DS1, or DS3
Tandem Transmission (TT) Transport to/from end offices via common transport circuits Tandem MOU and per tandem MOU per mile, based on V&H coordinates
Tandem Switching (TS) Charge for minutes switched by CenturyLink-owned Access Tandems Tandem MOU
Common Transport Multiplexing (CT MUX) Transport of MOUs between Access Tandems and subtending end offices via common facilities Tandem MOU
Tandem Trunk Port charge (ATTP) Fee per trunk terminated on the SWC side of the Access Tandem Flat rate per trunk
Rate Category: Local Switching
Local Switching (LS) Switching for originating minutes performed at the end office, host, RSS or RSM Originating MOU
End Office Shared Port (EOSP) Transport charge for originating MOUs between the Access Tandem and end office Originating MOU
End Office Dedicated Trunk Port (DED TP) Port connection linking the SWC of the POP to end offices Flat recurring per trunk
Rate Category:  Common Line
Carrier Common Line (CCL) Carrier Common Line Access Service provides for the use of Telephone Company common lines by customers for access to end-users. MOU
Rate Category:  Nonrecurring Charges
Including, but not limited to:
-Installation of Service
-Installation of Optional Features
-Service Rearrangements
One time charge for installation or change of services. flat rated

To aid in better understanding recurring rate elements, diagrams depicting the Switched Access rate structure can be found in the CenturyLink Operating Companies F.C.C.Tariff, and applicable state tariffs.

Tariffs, Regulations and Policies

Tariffs, regulations and policies are located in the CenturyLink Operating Companies F.C.C.Tariff, and applicable state tariffs.

Identification and Rating of VoIP-PSTN Traffic

VoIP-PSTN Traffic is traffic exchanged between a Telephone Company end user and the customer in Time Division Multiplexing ("TDM") format that originates and/or terminates in Internet Protocol ("IP") format. The FCC Tariff governs the identification and compensation of VoIP-PSTN Traffic required by the Federal Communications Commission in its Report and Order in WC Docket Nos. 10-90, etc., FCC Release No. 11-161 (Nov 18,2011).

A customer may update their PVU factors quarterly using methods outlined in the FCC Tariff. If the customer submits factor updates, it must submit no later than 15 days after the first of January, April, July and/or October each year, based on data for the prior three months, ending the last day of December, March, June and September, respectively. The revised PVU factors will serve as the basis for future billing and will be effective the next bill date, and shall serve as the basis for subsequent monthly billing until superseded by new PVU factors.

Quarterly PVU Factor Updates

A standard CenturyLink Factor for must be used for submitting Quarterly Factor updates to CenturyLink. The PIU/POM/PCL/PVU Quarterly Update Form can be found on the CenturyLink Wholesale Website. IXC Forms.

Optional Features

Carrier Identification Parameter (CIP)

Carrier Identification Parameter, or CIP, is an optional switching feature which identifies and transmits the Carrier Identification Code (CIC) of the presubscribed carrier or the Access Code (101XXXX) dialed by the calling party to the customer as part of the Initial Address Message (IAM). CIP is available with originating CST3 and Feature Group D Switched Access Service from suitably equipped SS7 end offices and tandems on a per trunk basis.

CIP functionality allows the IXC to combine individual carriers or services on one trunk group between the End Office or Access Tandem and the IXC switches. The CIP allows the IXC to consolidate trunk groups by having the ability to identify the carrier or traffic type on the other end.

CIP is an optional SS7 parameter that supports Interexchange Carrier Interconnection using Integrated Services Digital User Part (ISUP) call signaling. The CIP is included in the SS7 Initial Address Message (IAM) used in ISUP connections. The ability to include the CIP must be present in Access Tandems and Equal Access End Offices that terminate on the IXC.

Depending upon the type of access tandem and the signaling used between the access tandem and the end office, CIP may or may not be available. In some instances, the access tandem can create the CIP even when it is not passed by the end office. There are other optional features available for Switching, Transport Termination and Line Termination. These optional features are described in CenturyLink Operating Companies F.C.C.Tariff, and applicable state tariffs.


Service Features Benefits
Feature Group A
  • Lineside connection
  • LATA-wide terminations
  • 7 digit local number to collect long-distance traffic from multiple end-users (origination)
  • Resale with second dial tone
  • Low capital investment
  • Access to Local Calling Area for originating traffic
  • Lower long-distance rates for end-users
  • Inexpensive way to enter new markets
  • Local exchange tariff options
Feature Group B
  • Trunkside switching
  • Originating, terminating or 2-way trunking available
  • Nationwide 950-XXXX telephone number provided by NANPA
  • Available via direct routing to an end office or tandem switching
  • Provides answer/disconnect supervision
  • End-user PIN (personal identification number) for validation and billing
  • Provides nationwide single number for end-user customers
  • Better sound quality (than FG A)
Feature Group C
  • Available only to AT&T for trunkside access to non-EA end
  • N/A
Feature Group D
  • Trunkside switching
  • Originating, terminating or 2-way trunking available
  • Available via direct routing to an end office or tandem switching
  • Allows end-user access via presubscription (1+) or casual dialing (101XXXX)
  • Provisioned with wink start, answer and disconnect supervision
  • Available with MF or SS7 signaling
  • Enables direct-dial service
  • Fewer numbers for end-users to dial
  • Enhances International calling
  • Provides the best sound quality
  • Provides a full range of complementary services
  • Provides an equal opportunity for fair competition
  • With SS7 signaling, offers highly-requested end-user services, such as CLASS
  • ANI (automatic number identification) and CDR (call detail records) in industry standard AMA/BAF format


CenturyLink Switched Access Service enables the carrier to offer the high quality voice connections that long-distance users expect from the PSTN (Public Switched Telephone Network), at reasonable rates. For example ABC Carrier offers a host of products to end-user customers, including 1+ interstate long-distance service, and wants a low MOU rate that enables access to multiple end-users within selected LATAs.


Product Prerequisites and Pre-Ordering

Interexchange Carriers that plan to originate or terminate intra or interstate traffic must determine if they need to apply to the local Public Utilities Commission or Corporation Commission to obtain a Certificate of Public Convenience and Necessity (CPCN). The carrier must obtain an ACNA (Access Customer Name Abbreviation) from Iconectiv, and CIC (Carrier Identification Code) from NANPA, and then is able to set up an account with the CenturyLink Wholesale Center for Customer Service. They must also submit a Letter of Intent to the CenturyLink Sales Executive or Service Manager on their companyís letterhead.


Switched Access Services are ordered using the Access Service Ordering Guidelines (ASOG) forms.

The ASOG forms are nationally agreed upon by the Order and Billing Forum (OBF)

CenturyLink Switched Access Service is ordered by completing an Access Service Request (ASR) form.

If CenturyLink, through its own fault, fails to meet the Company committed Service Date, the customerís bill shall be shall be credited at the same rate at which they were billed, however the credit will not be provided if a credit of the same non-recurring charge for the same service is provided under other provisions of the Tariff. See CenturyLink Operating Companies F.C.C.Tariff, and applicable state tariffs.

Provisioning and Installation

Feature Group B and D (FG B-D) services provide a trunkside termination and are provided at CenturyLink-designated end office switches routed either directly to an end office or via CenturyLink Access Tandem switches.

When trunked directly from the carrierís point of termination (POP) to the end office, FG B-D services provide originating and/or terminating service to only the NXXs served by that end office.

When trunked to an Access Tandem, FG B-D services provide originating and/or terminating service to all end offices that subtend that tandem.

When FG B-D services are directly routed to an end office, the Switched Transport configuration is composed of an Entrance Facility (EF) and Direct Trunked Transport (DTT) facility to an end office. When it is switched through an Access Tandem, the configuration is composed of an EF, a DTT facility between the Serving Wire Center and the Access Tandem, and Tandem Switched Transport (TST) from the Access Tandem to the end offices subtending the access tandem. For additional flat and usage elements see diagrams in CenturyLink Operating Companies F.C.C.Tariff.

Maintenance and Repair

When Switched Access facilities are out of service for 30 minutes or more, a credit of 1/1440 of the monthly charge for each 30 minute period or major fraction thereof, is allowed.

When usage sensitive rate elements are out of service for 24 hours or more, a credit of 1/30 of the monthly charge for each 24-hour period or major fraction thereof, is allowed.

See CenturyLink Operating Companies F.C.C.Tariff, Section 2.4.4

An IXC can initiate a report of trouble by calling the Service Repair Hotline at (866) 874-6790 or by sending an email to RCC@centurylink.com.


CenturyLink bills Switched Access Services using our Carrier Access Billing System (CABS).

Feature Group service is a usage sensitive service. The Telephone Company at either the end office switch or the Access Tandem switch records Minutes of Use (MOU). These charges are in addition to the flat, recurring charges that are billed for Switched Transport elements, such as Entrance Facility, Direct Trunked Transport, and Multiplexing (MUX) that are billed on the CABS Facility Billing Account Number.

Feature Group usage sensitive elements are billed on the Switched Access Bill,

  • Access usage per MOU elements:
    • Local Switching
    • Interconnection Charge
    • Local Transport Facility and Termination
    • Tandem Switching
    • Multiplexing (Common Transport MUX)
    • Common Trunk Port
    • Carrier Common Line
    • Breakout of individual message type

Feature Group flat-rated elements are billed on the Facility bill:

  • Flat-rated elements:
    • Entrance Facility
    • Direct Trunked Transport
    • Multiplexer
    • Tandem Trunk Port
    • End Office Dedicated Trunk Port


CenturyLink contact information is located in Wholesale Customer Contacts.

For existing Customers operating in the CenturyLink QC territory, please contact your Service Manager for all questions. If you do not know who your CenturyLink Service Manager is, click here for additional information.

Last Update: October 19, 2018