scope:

Scope and purpose

This standard specifies the service capabilities of the Call Hold service within the context of an Integrated Services Digital Network (ISDN). The Call Hold service allows a served user to interrupt B-channel communications on an existing call and then subsequently, if desired, re-establish communications. The associated switching and signaling specifications are also provided. This service may be made available on demand or in a subscription arrangement. The interaction of this service with other service capabilities defined in American National Standards is also included. The purpose of this standard is to allow maximum compatibility among public-, and user-owned telecommunications equipment in order to increase the attractiveness and usefulness of ISDN-based capabilities.

Application

This standard applies to ISDN Basic Accesses and Primary Rate Interfaces and is intended to supplement the Basic Circuit Mode call procedures described in American National Standard for Telecommunications - Integrated Services Digital Network (ISDN) - Layer 3 signaling specification for circuit-switched bearer service for digital subscriber signaling system number 1 (DSS1), ANSI T1.607-1990 and American National Standard for Telecommunications - Signaling system number 7 (SS7) - Integrated services digital network (ISDN) user part, ANSI T1.113-1988. It should be used in conjunction with the other American National Standards for ISDN supplementary services for a complete understanding of the interactions between this and other services. This supplementary service is applicable to the Speech, Voice-Band Data (3.1 kHz audio), and Data (64 kbit/s unrestricted) Circuit-Mode bearer services identified in American National Standard for Telecommunications - Integrated services digital network (ISDN) - Minimal set of bearer services for the basic rate interface , ANSI T1.604-1990 and American National Standard for Telecommunications - Integrated services digital network (ISDN) - Minimal set of bearer services for the primary rate interface, ANSI T1.603-1990.