TSGs are clocks that are used throughout service-provider networks, frequently as the building integrated timing supply (BITS) for a central office.
Digital switching systems and some transmission systems (e.g., SONET, RREX, LUBI) depend on reliable, high-quality synchronization (or timing) to prevent impairments. To provide this, most service providers use interoffice synchronization distribution networks based on the stratum hierarchy and implement the BITS concept to meet intraoffice synchronization needs.
A TSG is clock equipment that accepts input timing reference signals and generates output timing reference signals. The input reference signals can be either DS1 or composite-clock (CC) signals, and the output signals can also be DS1 or CC signals (or both). A TSG is made up of the six components listed below: