2 Wire Digital

Overview

This service provides a digital 2-wire enhanced channel. It is equivalent to a 2-wire loop less than 18,000 feet from the NID at the end user's premises to the main distributing frame (which is connected to the CLEC's collocation arrangement) in the Verizon central office in which the end user is served. The 2-wire Digital - ISDN BRI loop is only available to the CLEC for use in conjunction with the provision of local exchange service and exchange access to its end users.

Description

The primary difference between a basic analog loop and a 2-wire Digital - ISDN BRI loop is that the latter is qualified to support basic rate ISDN. Generally, metallic loops are capable of meeting the requirements if they are less than 18,000 feet long and have transmission characteristics as described in the technical description below. Verizon will determine which facilities are capable of meeting the 2-wire digital loops requirements at its sole discretion. Verizon will select and assign the qualified loop. The Verizon loop process will assign the required facilities requested for the specific loop ordered by the CLEC. For new loops, the CLEC can order premium (ISDN capable) loops. Most digital loop carrier systems can support 2-wire Digital - ISDN BRI loop, provided the metallic path resistance from the remote terminal to the NID at the end user location is less than 900 ohms. Design practices for the deployment of digital loop carriers require that this condition be met.

Another significant difference between analog and digital loops is that while analog loops can be provided to virtually any end user, digital loops cannot. Qualified loops may not be available at each end user's location. For example, all existing loops in New York City are not ISDN capable. The loop facility assigned will be of a length that is not affected by load coils/bridge taps, thus allowing for the "element" to be ISDN capable. To determine the availability of 2-wire Digital - ISDN BRI loops in Verizon-North, the CLEC may access the Verizon Web GUI loop qualification function, categorized under pre-order functions. For migration, current ISDN services do not require qualification. If requesting to upgrade an existing loop, the CLEC may want to verify loop qualification. Verizon-South will provide a 2-wire Digital - ISDN BRI loop to most locations. Future offerings in Verizon-South may provide access to a loop qualification database.

Availability

This element is only available to the CLEC for use in conjunction with the provisioning of local exchange and associated exchange access service to its end users.

Pricing

Non-recurring charges are billed for service orders, service connections (other charges), central office wiring (if applicable), installation dispatches (if applicable), and manual interventions (if applicable). Additional non-recurring charges are assessed per day for expedited orders. There are recurring, monthly charges for 2-wire digital loops and DS0 service access. There is a specific USOC for premium 2-wire loops. Network Channel (NC) codes and Network Channel Interface (NCI) codes are required for all orders except migrations (“as is”) in New York.

Pricing and applicable USOCs may vary by state jurisdiction and pursuant to individual carrier interconnection agreements.

See your federal and tariffs for detailed information.

Detailed Information

A 2-wire Digital - ISDN BRI loop is physically provisioned in two ways. Most 2-wire Digital -ISDN BRI loops consist of copper twisted pairs extending from the central office Main Distributing Frame (MDF) to the end user's location. The first diagram depicts the 2-wire copper loop; (CKL 1 is the CLEC's collocation arrangement and CKL 2 is the end user's address.)

The second option uses a combination of a Universal Digital Loop Carrier and a twisted pair to reach the end user. The second diagram depicts the 2-wire digital loop provided on a universal digital loop carrier; (CKL 1 is the CLEC's collocation arrangement and CKL 2 is the end user's address.)

2-wire Digital - ISDN BRI loops must be provided on non-loaded facilities, and cannot be provisioned if the facilities have bridge taps in place. 2-wire Digital - ISDN BRI loops are 2-wire applications that require one pair to support service provisioning.

Due to the unique transmission requirements, service availability is further limited to those end user locations where suitable facilities exist. The CLEC's request for unbundled 2-wire digital - ISDN BRI loop must conform to the existing ISDN service availability limitations. Therefore, 2-wire digital - ISDN BRI unbundled loops are only available where loops conform to transmission specifications that support ISDN service.

For more information, please refer to the Unbundled Digital Loop Technical Specifications document.