ABSTRACT: GR-561 replaces TR-TSY-000561, Issue 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.

The two-party line feature provides basic telephone service to two customers sharing the same line. The feature requires that the system have the capability to distinguish between each party upon origination and termination and to provide a means for each party to call the other party. Features assigned to each party of the two-party line may vary, i.e., party one may have Dual-Tone Multifrequency (DTMF) service, and party two may have rotary dial. This GR describes the view of Telcordia on generic requirements for the two-party line feature.

GR-560, GR-561, GR-562, GR-563, GR-564, GR-565, GR-568, and GR-569 replaced TR-TSY-000521 and TA-TSY-000229.