TIA TIA-876

Abstract

This standard defines a model of the characteristics of the North American access network that determine xDSL modem transmission performance. It is intended to be the basis for performance testing of systems consisting of central site modems that interface with the broadband telecommunications network and remote modems at the customer premises. The model includes specifications for the configuration and setup of suitable simulator equipment used in evaluations and comparisons of such modem systems. <br><strong>Warning</strong> <br>The network models represented in this specification do not model all possible connections that can be encountered between a central site modem and a remote modem in the North American loop plant. <br>Limitations on this model: <br>1. This model does not include very low-probability connection scenarios. <br>2. Steady-state loop current and loop battery parameters are not specified. Refer to ANSI/EIA/TIA 496-A for information on those parameters. <br>3. This model does not reflect the characteristics of network equipment operating outside of its normal operational specifications, referred to as "trouble" conditions. <br>4. The network transmission impairments used in this model are those that exist in the access network and affect the performance of present-day DSL modems. New network equipment or new modem designs may result in additional parameters, not currently characterized, becoming important. Results derived from tests using this model are suitable for comparative purposes, and should be viewed as no more than a rough estimate of expected performance over the real network. <br>5. This standard models the DSL access network over the frequency range of 0 to 1.104 MHz. It is not intended for use in testing VDSL modems. <br>While the percentages of network model coverage (NMC) derived from the tests contained herein may provide a suitable basis for comparing modems, they should only be considered indicative of potential coverage of the real network.