ABSTRACT: This document contains generic criteria for Timing Signal Generators (TSGs), which are clocks that are used throughout service provider networks, most frequently as the Building Integrated Timing Supply (BITS) for a central office. This GR is expected to be of use to service provider synchronization coordinators, TSG suppliers, and manufacturers of equipment that interfaces with TSGs.

GR-378 is the only document that defines and provides both interface and equipment criteria for TSGs intended for use in North American telecommunications networks. In addition, it is the only document that provides criteria for TSGs supporting both traditional synchronization distribution using DS1 and CC reference signals, and the increasingly important areas of Time of Day (ToD) and packet-based timing distribution.

What's New in Issue 4:

• Contains a new section that provides information and criteria related to Time of Day (TOD) synchronization within networks and the distribution of synchronization over packet-based networks
• Includes information on a TSG's possible support of frequency reference output signals other than the DS1 and CC signals traditionally used in North American applications.
• Provides various clarifications and updated standards references.