4 Wire Digital
Overview
What It Is
Verizon's Unbundled 4-Wire Digital Loop delivers DS1-type capabilities over a loop on a two-point digital channel. This facility transmits two-way serial, bipolar, return-to-zero and isochronous digital signals simultaneously. A four-wire DS1-compatible Loop is capable of a transmission rate up to 1.544Mbps.
How It Works
An Unbundled 4-Wire Digital Loop connects your customer location to your collocation or EEL arrangement, where available, in Verizon's central office. The provisioning flow is designed using our Operations Support System. Interfaces at your DSX-1 termination and the customer's Network Interface Device are 4-wire connections. The loop uses various transmission technologies, such as metallic cable facilities with or without repeaters and fiber optic transport systems.
Description
This service provides a digital high-capacity capable loop on a two-point digital channel that allows simultaneous two-way transmission of serial, bipolar, return-to-zero, isochronous digital signals at a speed of 1.544 Mbps +/-32ppm.
DS1 loops provide a connection from and including the NID at the end user's premises to a point of interconnection at the EEL arrangement (where Verizon makes such arrangements available) or at the point of interconnection at the POT bay at the CLEC's collocation presence in the Verizon central office where the end user is served.
Availability
This element is only available to the CLEC for use in conjunction with its provision 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). There are also non-recurring charges for conditioning of DS1 Loop, CLEC Not Ready - In and Out and Trouble Dispatch Misdirect - In and Out. Additional non-recurring charges are assessed per day for expedited orders as applicable.
1. Non-Recurring charge applied only once to the CABS Collocation bill when a Virtual Collocation arrangement is installed in a Verizon central office. Monthly Recurring charge applied to a UNE bill starting when a particular UNE (DS1 loop) is connected to the Virtual Collocation arrangement.
2. There are recurring, monthly charges for the high capacity 1.544 Mbps loop. In addition, cross-connect charges apply. Network Channel (NC) and Network Channel Interface (NCI) codes are required for all orders.
Pricing and applicable USOCs may vary by state jurisdiction and pursuant to individual carrier interconnection agreements.
See your federal and state tariffs for detailed information.
A digital high-capacity loop provides a two-point digital channel, which provides for simultaneous two-way transmission of digital electrical signals at a transmission rate of 1.544 Mbps +/-32ppm.
The DS1 loop carries digital signals at the rate of 1.544 Mbps between an end user location and a CLEC collocation arrangement (see diagram) or EEL arrangement (where Verizon makes such arrangements available) located in a Verizon central office. An unbundled digital DS1 high-capacity loop can be interconnected with a CLEC network through a physical or virtual collocation arrangement, or onto an EEL arrangement (where offered).
The provisioning flow is a designed flow involving a Verizon Operations Support System (OSS). A circuit identification in Circuit Location Serial (CLS) format is used to identify the unbundled element. The A and Z of the circuit is the Common Language Location Identifier (CLLI) of the CLEC collocation arrangement and the CLLI of the end user location respectively.
The interface at the CLEC DSX-1 termination in the Verizon central office is 4-wire, and the interface at the end-user NID is 4-wire. The conductors of the CLEC or end user transmit pair are called tip and ring and the conductors of the CLEC or end user receive pair are called tip 1 and ring 1.
The transmission channel between the DS1 interfaces consists of 4-wire facilities. DS1 is provided using a variety of loop transmission technologies including metallic cable facilities with or without repeaters or fiber optic transport systems.
The DS1 loop enables full duplex 1.544 Mbps digital transmission. The 1.544 Mbps line rate supports an 8 Kbps framing format and 1.536 Mbps of payload data. The DS1 loop supports either the Superframe (SF) or Extended Superframe (ESF) framing formats as specified in ANSI T1.403-1995 \[4\].
The DS1 loop is available with either the AMI or B8ZS line codes as specified in ANSI T1.403-1995 \[4\]. The DS1 loop provides an electrical DS1 interface at the RDP that meets the network requirements in ANSI T1.403-1995 \[4\].
The DS1 interface provided by Verizon does not ordinarily deliver direct-current power to the NID via the simplex leads of the transmit and receive pairs. However, when Verizon employs metallic facilities and no loopback device is deployed, direct-current power may appear at the NID on the simplex leads of the transmit and receive pairs. In such cases, the CLEC or end user equipment must provide a direct-current connection between the simplexes of the transmit and receive pairs.
In addition, customer equipment shall not apply voltages to the End User-Point of Termination (EU-POT) other than those described in ANSI T1.403-1995.
Diagrams
