ABSTRACT: GR-782 replaces TR-TSY-000782, Issue 2, 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.
With the rapid growth of optical fiber transmission facilities, it is appropriate to describe generic requirements for a
high-capacity digital switch trunk interface. A high-capacity trunk interface on the digital switch that is compatible with Synchronous
Optical Network (SONET) allows interconnection with SONET Network Elements (NEs). SONET defines Optical Carrier (OC-N) signals and
their equivalent electrical Synchronous Transport Signals (STS-N). These signals operate at a rate of N x 51.840 Mb/s.
This GR provides the view of Telcordia on generic criteria for an OC-N interface to a digital Local Access and Transport Area
(LATA) Switching System (LSS) to be used in the trunk networks of the Local Exchange Carriers (LECs). The functions of the typical
SONET digital switch interface will be described as pertaining to the intraoffice environment. The intraoffice environment is viewed as
a central office where many SONET NEs are co-located and interconnected via SONET signals. Special attention is focused on the overhead
that need to be processed on the received signal. The SONET digital switch interface will terminate an OC-N signal that transports byte
synchronous Floating Virtual Tributary-1.5s (VT1.5s). This mode allows direct identification and access to the 24 DS0 (Digital Signal
0) channels per VT1.5 without framing on the Digital Signal 1 (DS1) Signal.