Integrated Services Digital Network (ISDN) – Basic Access Interface for S and T Reference Points (Layer 1 Specification)
|Publication Date:||1 July 1991|
Scope and purpose1)
This standard defines the layer-l characteristics of the user-network interface to be applied at the S or T reference points for the basic interface structure defined in CCITT Recommendation 1.412. The reference configurations for the interface are defined in CCITT Recommendation 1.411 and are reproduced in figure 1. The definitions and characteristics of the functional groups are also provided in CCITT Recommendation 1.411. A notation of the "U" reference point has been added. This standard is intended to be consistent with CCITT Recommendation 1.430.
In this standard, the term "NT" is used to indicate network-terminating layer-l aspects of NT1 and NT2 functional groups, and the term "TE" is used to indicate terminal terminating layer-l aspects of TEl , TA, and NT2 functional groups, unless otherwise indicated. However, in 7.2 only, the terms "NT" and "TE" have the following meaning: the term "NT" is used to indicate the layer-l network side of the basic access interface; the term "TE" is used to indicate the layer-l terminal side of the basic access interface.
NOTE - The loop transmission system utilizing one metallic pair and providing for ISDN basic access is referred to as the Digital Subscriber line and is specified in terms of the interface on the network side of the user-end termination in American National Standard for Telecommunications - Integrated services digital network (ISDN) - Basic access interface for use on metallic loops for application on the network side of the NT (Layer 1 specification), ANSI T1.601-1992.
1) This standard is similar to CCITT Recommendation 1.430. The individual departures of this standard from the provisions of CCITT Recommendation 1.430 are described in annex M. Applicable clauses and subclausj es that contain departures from the original CCITT document are highlighted by the footnote number "1".