ABSTRACT: Generic Requirements in GR-866 describe the switching and signaling to support ISDN Message Service. ISDN Message Service is a
collection of features used to assist a Message Storage and Retrieval (MSR) System in providing call coverage for and notification of
waiting messages to its client users.
This GR provides requirements that will enable switch suppliers and suppliers of MSR Systems to provide a more reliable interface
for answering calls, as well as the ability to centralize the call answering function at one switch while serving client users at
different switches in the same LATA. The GR also provides requirements to support for non-ISDN client users and MSR Systems served by a
Simplified Message Desk Interface (SMDI). Revision 1 to GR-866-CORE provides additional requirements for procedures and signaling to
support additional Phase II capabilities for providing more useful information to client users about the messages that have been stored
at the MSR System, e.g., an indication of the number of waiting messages and of text information for display to ISDN client users along
with message waiting notification.
This revision also resolves industry comments about non-call-associated signaling in this application.
GR-866 replaced TR-NWT-000866 and TA-TSY-000028.
This GR also includes one or more Issue List Reports (ILRs) that details open or closed technical issues in the main document. The
ILR(s) are automatically sent free of charge to the GR document purchaser.
Revision 1, dated February 1999, is included in this document.