CenturyLink™ Local Services Platform (CLSP™ ) - Integrated Services Digital Network (ISDN) Basic Rate Interface (BRI) - V7.0
Note: This product is also known as Qwest Local Services Platform® (QLSP®).
CenturyLink™ Local Services Platform (CLSP™) products provide local exchange telecommunications services to end-users on behalf of Competitive Local Exchange Carriers (CLECs) at competitive wholesale commercial rates. General information about CLSP can be found in CenturyLink™ Local Services Platform (CLSP™) - General Information.
CLSP Integrated Services Digital Network (ISDN) Basic Rate Interface (BRI) is an all-digital communications technology that provides services and capabilities not available through standard analog technology to your end-users that is functionally equivalent to CenturyLink's retail ISDN BRI services. The ISDN digital architecture provides a high-speed, integrated transfer of voice, data and video over the same line, using the Public Switched Network (PSN). CLSP ISDN BRI products are finished services requiring neither CLEC collocation nor other CLEC network involvement, and are combinations of the following network elements:
- An ISDN BRI Capable Unbundled Local Loop
- A Digital Line Side Port (Supporting ISDN BRI) including Local Switch Usage and any optional switch features
- Shared Transport
ISDN BRI provides for two simultaneous voice connections and a low-speed data connection over existing telephone lines. The loop portion of this service is provided on a 160 kilobits per second (Kbps) Digital Subscriber Line (DSL) channel that has an information rate of 144 Kbps and is divided into three channels:
- Two "B" channels capable of providing switched voice and switched data transmissions, allowing two simultaneous separate 64 Kbps connections of either type. B channels do not support packet switched data transmissions or out-of-band message signaling. Depending on the end-user's Customer Premises Equipment (CPE), the two B channels can be combined (bonded) into one high-speed 128 Kbps link.
- One "D" channel capable of 16 Kbps. The D channel supports out-of-band message signaling and packet data functionality and does not support voice applications. This channel can simultaneously route up to 15 data calls.
In each ISDN-capable switch, ISDN BRI configuration groups or capability packages are programmed into the ISDN BRI common block according to Telecordia National Standards. Telecordia ISDN Ordering Codes (IOCs) identify the different pre-programmed configuration groups or capability packages. The CPE vendor will work with you to select the appropriate IOC for your needs. If you require an ISDN BRI arrangement that is not supported by an IOC, you can request the specific arrangement of features and functions Universal Service Order Codes (USOCs) and Field Identifiers (FIDs) to accommodate your needs.
The CenturyLink ISDN BRI standard feature package includes all standard features identified in the Tariffs/Catalogs/Price Lists. You should contact a CPE vendor to determine if your end user's CPE can support standard features and to learn more about how the features work with the CPE.
|Standard voice features:
|Call Appearances (CA)
|The position(s) on a terminal to which numbers are assigned. A Directory Number (DN) can be shared by more than one ISDN terminal. The quantity and/or position of CA for the Primary Directory Number (PDN), Secondary Directory Numbers (SDN) and Shared Call Appearances (SCA) are limited by the standard or non-standard configuration and capability package selected depending on the CPE. A total of six CAs per terminal are included in the standard configuration and capability package.
|Call Exclusion - Automatic Exclusion
|Allows you to restrict other end-users that share a DN from bridging onto a call. This option is automatically activated when you pick up the receiver to receive or place a call.
|Call Exclusion - Manual Exclusion
|Allows you to restrict other end-users that share a DN from bridging onto a call. This option is activated by pressing a designated button before dialing or during the call.
|Call Forwarding Busy Line
|All calls (pre-programmed), forwards all voice calls that reach a busy PDN to be forwarded to another telephone number either within the same CO, or in a different CO.
|Call Forwarding Don't Answer
|All calls (pre-programmed), forwards all voice calls terminating to an idle PDN to be forwarded to another number when the called PDN does not answer after a predetermined number of seconds.
|Call Forwarding -Variable, All Calls
|Forwards all PDN voice calls to another telephone number by pressing a designated Call Forwarding-Variable button. The forward-to number is customer changeable. You must activate or deactivate the forwarding function by using either an access code or a designated feature button.
|Allows you to place a call on hold by pressing a designated button.
|Allows you to transfer a call to a third party by pressing a designated button.
|Caller Identification Blocking, Per Call
|Allows you control the delivery of the caller name and/or DN by dialing an access code before each call to change the indicator from public status which delivers caller information or to private status preventing the delivery of caller information.
|Calling Line Identification -Incoming Calling Line Identification (ICLID)
|Displays the call number identification and the calling name identification (including non-published and non-listed DNs) prior to the call being answered. Callers have the ability to inhibit the display of calling party information to the terminating number. ICLID is provided to the PDN and to any associated SDNS. ICLID cannot just display to the PDN when the number is shared.
|Calling Line Identification - Outgoing Calling Line Identification (OCLID)
|Provides you with information about the called party and the facility or destination.
|Allows you to establish a three-way conference call by pressing a designated button.
|Display is part of selected ISDN terminals providing time, date, calling telephone number, CA identification, called telephone number, and feature activation operation information.
|Allows you to drop the last party added to a conference call or to disconnect a two-party call.
|Allows two end-users to be part of an intercom group, allowing calls to be completed by pressing the designated feature button without dialing the entire telephone number.
|Message Waiting Indication
|Available on PDNs and notifies you of a message waiting by providing either an audible stuttered dial tone or a visual illuminated light on the telephone set. Messages may be retrieved by calling the message service center or by accessing a voice mail system.
|Primary Directory Number (PDN)
|The main telephone number assigned to the ISDN terminal. If more than two terminals are attached to a Digital Subscriber Line (DSL), an additional PDN charge will apply.
|Ringing Options - Abbreviated Ringing
|Abbreviated Ringing follows begins immediately for an incoming call and stops ringing after a designated number of seconds. Ringing for incoming calls that terminate on the SCA of a DN on a per-station basis.
|Ringing Options - Delayed Ringing
|Ringing for an incoming call is delayed for a designated number of seconds, however, the call indicator or status light begins flashing immediately. Ringing for incoming calls that terminate on the SCA of a DN on a per-station basis.
|Ringing Options - No Ringing
|Prevents ringing for an incoming call that terminates on a call appearance of that DN. Ringing for incoming calls that terminate on the SCA of a DN on a per-station basis.
|Ringing Options - Normal Ringing
|Ringing begins immediately for an incoming call and continues until the call is forwarded, answered or abandoned. Ringing for incoming calls that terminate on the SCA of a DN on a per-station basis.
|Secondary Directory Number (SDN)
|Any DN other than the PDN assigned to an ISDN terminal. If more than one SDN is assigned to a terminal, additional charges will apply.
|Shared Call Appearance (SCA)
|Allows several end-users to share one or more CAs for a particular DN. Origination of and termination of calls on one terminal will affect all terminals sharing the CA. All SCA must be provisioned from the same serving CO.
|Allows an end-user to dial frequently called telephone numbers by dialing 1- or 2-digit codes in place of the entire telephone number. A speed call list allows for up to 30 pre-programmed numbers per terminal.
|Standard Configuration Group
|An arrangement that associates a button of an ISDN station set to a feature.
|Standard B Channel Circuit Switched Data Features
|Call Forward-Busy Line
|Permits all circuit-switched data calls attempting to terminate to a busy PDN, to be redirected to another customer-specified DN. This feature can either be assigned to forward automatically or it can be assigned to a feature button that can be activated or deactivated by the end-user. If the feature is assigned to a feature button, dialing an access code and programming the new forward-to DN can change the forward-to DN.
|Call Forward-Don't Answer
|Permits all circuit-switched data calls attempting to terminate to an idle PDN to ring a specified number of seconds prior to being forwarded to a predetermined DN. This feature can either be assigned to an end-user on an active basis or it can be assigned to a feature button that can be activated or deactivated by the end-user. If the feature is assigned to a feature button, dialing an access code and programming the new forward-to DN can change the forward-to DN.
|Allows all circuit-switched data calls attempting to terminate to a line, to be redirected to another specified line. You must activate or deactivate the forwarding function by either using an access code or a feature button. If the feature is assigned to a feature button, dialing an access code and programming the new forward-to DN can change the forward-to DN.
|Standard D-Channel Packet Data Features
|X.25 Fast Select
|A function of the CPE and is used on a per-call basis allowing the end-user to send up to 128 octets in the end-user data field of the call request packet to a terminal with Fast Select Acceptance.
|X.25 Flow Control Parameter Negotiation
|Permits negotiation on a per-call basis of the flow control parameters associated with a given virtual call, such as packet size and window size for each direction of data transfer. The data window size and the maximum packet size are negotiated automatically during an X.25 data call.
|X.25 Logical Channels
|Virtual circuits rather than physical circuits are used to establish packet switch calls. When a virtual circuit is established, a logical channel is assigned at the CPE and the switch for the duration of the call. A virtual circuit does not use any capacity of the facility unless data is actually being transferred. Two logical channels are provided per DSL.
|X.25 Reverse Charging
|A function of the CPE and allows an end-user to assign billing to the called data telephone number on a per-call basis.
|X.25 Throughput Class Negotiation
|Permits negotiation on a per-call basis of the throughput class for each direction of data transfer associated with a virtual call. The data terminal can negotiate the throughput class for an X.25 data call.
ISDN BRI is available where facilities exist throughout CenturyLink QC.
Terms and Conditions
Depending on the end-user's CPE and the number of lines ordered, limitations may exist regarding how many ISDN devices can be supported or active at one time. In general, standard network interface CPE supports from one to eight ISDN devices (telephone, facsimile, desktop computers, video units, etc.) with the following limitations per loop:
|B Channel Terminals
|D Channel Terminals
|Maximum of two
|Maximum of six
|A packet device cannot share a telephone number with a B Channel terminal
|Maximum of eight
|Maximum of six
|Generally, a maximum of four D channel terminals is observed unless some devices are used only rarely. The sending and receiving process can be inhibited if numerous terminals are using the D Channel at the same time.
Speed, functions and usage of the channel terminals are determined by the CPE.
ISDN BRI is available in certain ISDN capable 5ESS and DMS-100 switches, and in some instances their remote switches. Other types of CO switches (such as DMS-10, Ericsson, etc.) do not have ISDN capability. Information describing how to determine ISDN BRI availability is described in the Pre-Ordering section.
Technical characteristics are described in the following:
- American National Standards Institute (ANSI) Standard Publications.
- Technical Publication , Unbundled Switch Elements, 77391
- Technical Publication , Interconnection - Unbundled Loop, 77384
- Telecordia Special Reports (SRs), SR-2275, Notes on the Network
Monthly recurring charges (MRCs) for CLSP ISDN BRI is the sum of the monthly recurring rates of the following elements:
- A Basic Rate ISDN Digital Capable UBL, provided in the Rate Sheet or Exhibit A of the applicable ICAs in effect between CenturyLink and CLEC,
- The Local Switching Network Element Digital Line Side Port (Supporting BRI ISDN) (including the flat switch port MRC plus Local Switching Minutes Of Use (MOU), provided in the CLSP Rate Sheet,
- Switch Features provided in the CLSP Rate Sheet,
- Shared Transport MOU provided in the CLSP Rate Sheet, and
- Any additional MRCs for other value added services, such as Operator Service (OS)/Directory Assistance (DA), CenturyLink Voice Messaging Service (VMS), Advanced Intelligent Network (AIN), etc., provided in either your ICA and/or CLSP Rate Sheets.
A non-standard configuration charge applies per button (USOC N3CPB) when establishing an ISDN BRI arrangement that is not supported by an IOC.
Non-recurring Charges (NRCs) for CLSP are provided in the CLSP Rate Sheet.
CLSP products include either one residential or one business directory listing (dependent on end-user application and the product requested) for each main telephone number, at no charge. Premium and privacy listings are also available. Regardless of residential or business directory appearance, all premium and privacy listings (with the exception of residential additional listings (e.g., USOC RLT) are categorized as business for rating purposes. Information describing directory listing availability and ordering is described in White Pages Directory Listings.
MRCs and NRCs are available in the Rate Sheet of your Commercial Agreement and/or the Rate Sheet or Exhibit A of the applicable ICA.
Nebraska CLSP circuits only:
Effective September 19, 2011, you must place either the USOC XCBO2 (2-wire) or XCBO4 (4-wire) on your CLSP LSR if your End-User is in an "Out of Town" location. Additional information on determining this classification is in Geographic Deaveraging - General Information.
Tariffs, Regulations, and Policies
CenturyLink VMS tariffs, regulations, and policies are located in state specific Tariffs/Catalogs/Price Lists.
Optional feature descriptions and ordering information can be found in Optional Features Ordering Information.
The following non-ISDN analog features and/or services are not compatible with ISDN BRI. If a non-compatible feature exists on an account to be converted, remove the features and/or services from the account prior to converting.
- Automatic Call Back
- Call Waiting
- Home Intercom
- Anonymous Call Rejection
- Call Forwarding Busy and Don't Answer (with certain types of CPE)
- Wide Area Telephone Service (WATS)/800 Service
Remember to verify with the CPE vendor that your end user's CPE can support the ISDN BRI features.
Features / Benefits
|All Digital Communications
|Integrated transfer of voice, data and video over the same line
ISDN BRI services provide voice only (circuit switched voice), voice and data (includes circuit switched voice, circuit switched data, and packet switched data), or data only (includes circuit switched data and packet switched data) applications.
If you are an existing CLEC and would like to amend your ICA and/or Customer Questionnaire, refer to Interconnection Agreement Amendments. To review and/or request preparation of a CLSP Agreement, visit Commercial Agreements.
General pre-ordering activities are described in the Pre-Ordering Overview.
Requirements for pre-ordering are described in Local Service Ordering Guidelines (LSOG) Pre-Order.
New ISDN BRI telephone numbers can not be reserved using EASE-LSR. CenturyLink will return telephone numbers to you on the Firm Order Confirmation (FOC). If your end-user wants to convert an existing non-ISDN telephone number to Resale ISDN BRI, check with your CenturyLink Representative to see if the telephone number can be converted. Availability of ISDN BRI in the end-user's serving office does not guarantee that the prefix will be compatible.
CenturyLink strongly suggests that you complete the ISDN loop qualification pre-ordering process in addition to the CO ISDN availability pre-ordering process so that you are able to determine ISDN BRI service and facility availability. ISDN-BRI pre-qualification is a two step process.
Step 1: Verify the availability of ISDN BRI in the serving CO by referring to Network Disclosures. Select the appropriate state for the end-user's CO location. If the ISDN BRI DATE column is populated with "Deployed", the service is available.
Step 2: Verify ISDN loop facility availability at the end-user's address as described in the EASE-LSR User's Guide.
Service is not guaranteed until the ISDN has actually been installed. In certain rare instances, Facility Check may not be able to determine a design problem that would prevent installation of the service. In this situation you would be notified via a jeopardy notice. Additional information on the jeopardy process can be found in the Provisioning and Installation Overview.
Backhauling provides dialtone from an ISDN equipped switch that is not the end-user's local serving wire center to the end-user's local serving wire center. All backhauling requests should be referred to your CenturyLink Representative.
It is important to review and understand the ordering procedures described in CenturyLink Local Services Platform (CLSP) - General Information.
General ordering activities are described in the Ordering Overview.
ISDN BRI service requests are submitted using the following LSOG forms:
- Local Service Request (LSR)
- End User (EU)
- Resale Service (RS)
- Directory Listing (DL)
Field entry requirements are described in the LSOG.
When requesting new ISDN BRI service, enter the ISDN Ordering Code (IOC) obtained from the CPE vendor. The IOC must be entered in the FEATURES field on the RS form.
If an IOC is not available, you must enter the USOC and FID information required for your ISDN BRI arrangement in the FEATURE and FEATURE DETAILS fields of the RS form. For assistance in ordering refer to 5ESS Ordering Information or DMS-100 Ordering Information and Optional Features Ordering Information
To request Loop Conditioning, in the REMARKS field of the LSR form include an entry of "Loop Conditioning authorized". Without an entry in REMARKS, you have not authorized Loop Conditioning. If the service does not loop qualify and if you have not authorized Loop Conditioning the order will be rejected.
Disclosure information and other LSR instructions are available in Network Disclosures.
Provisioning and Installation
General provisioning and installation activities are described in the Provisioning and Installation Overview.
Upon receipt of an accurate and complete LSR including authorization of Loop Conditioning, you will receive a Firm Order Confirmation (FOC) based on the standard interval found in the Service Interval Guidelines (SIG). If at any time after you receive the FOC, and prior to the scheduled due date, CenturyLink determines that loop conditioning is required, CenturyLink will apply the Loop Conditioning interval and will re-FOC your LSR reflecting the new scheduled due date. The interval will begin on the date CenturyLink determines that loop conditioning is necessary and a supplemental LSR is not required.
If at any time after you receive the FOC, and prior to the scheduled due date, CenturyLink determines that the loop cannot be conditioned to loop qualify, you will receive a jeopardy notification via EASE-LSR. The jeopardy notification will provide you information on how to proceed.
Maintenance and Repair
General maintenance and repair activities are described in the Maintenance and Repair Overview.
Customer Records and Information System (CRIS) billing is described in Billing Information - Customer Records and Information System (CRIS).
CenturyLink has developed and provides an array of training courses that our CLSP customers will find beneficial. The following courses are especially recommended:
- Local CenturyLink 101: "Doing Business With CenturyLink"
- EASE-LSR Directory Listings
- EASE-LSR "Hands On
View these and additional CenturyLink courses by clicking on Course Catalog.
CenturyLink contact information is located in Wholesale Customer Contacts.
Frequently Asked Questions (FAQs)
1. Is CLSP usage sensitive?
Shared Transport MOU and Local Switching MOU apply per line in accordance with MRCs provided in the Rate Sheet of your Agreement.
2. May I convert existing CenturyLink Retail lines to CLSP?
You may order new CLSP ISDN BRI service or convert existing retail or resale ISDN BRI or SLS to CLSP ISDN BRI
Last Update: March 30, 2015
Last Update: November 2, 2023
CenturyLink™ Local Services Platform and CLSP™ are Trademarks of CenturyLink
5ESS® is a Registered Trademark of Lucent Technologies, Inc.
DMS is a Trademark of Nortel Networks.