ABSTRACT: GR-577 replaces TR-TSY-000577, 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. For your convenience, the revision has been interfiled into GR-577.

Three-Way Calling (TWC) non-Centrex is a custom calling feature that allows a customer to add a third party to an existing conversation without operator assistance. The party initiating TWC may hold one party with privacy exclusion while dialing and talking with another party (referred to as consultation hold) and can later include the held party in TWC. The added party may be dropped from the connection by a flash from the initiating party. This Generic Requirements document (GR) provides the view of Telcordia on generic requirements for TWC.