ABSTRACT: GR-571 replaces TR-TSY-000571, Issue 1 and Revision 1, but contains NO TECHNICAL CHANGES from that original document. It has been issued strictly to conform with the new Telcordia Technologies document format and GR process, and carries a new issue number and date. Revision 1 to TR-TSY-000571 has been interfiled into GR-571.

Occasionally, a subscriber may miss an important telephone call because he or she was already talking to someone else when the call came in. These subscribers need an inexpensive service that would allow them to place one call on hold while they answer the incoming call. This Generic Requirements document (GR) describes the view of Telcordia on generic requirements for Call Waiting (CW), which informs a busy station user, by a burst of tone, that another call is waiting. This document also includes a Call Forwarding Don't Answer (CFDA) interaction. The modification is intended to ensure a uniform feature interaction in a multi vendor environment.