Symmetricom 1000, 1100 manual Operating Modes, Communication, Clocks, SSU Mode

Chapter 1 Overview of the TimeProvider

Operating Modes

The TimeProvider outputs are arranged into four groups of eight outputs per group in the Main shelf and four groups of eight outputs per group in the optional Expansion panel. Each group is labeled A, B, C, and D, and can be configured independently.

Communication

Three communications ports provide access to the TimeProvider: Ethernet, local Craft serial port, and a Remote serial port. These ports are described in detail in Communication Ports, on page 34.

Clocks

The TimeProvider’s clock design includes a highly stable ovenized Quartz crystal or Rubidium oscillator with Direct Digital Synthesis (DDS) to produce accurate synchronization outputs. In a dual-IOC configuration, the clock function is redundant to provide protection, and you can mix and choose any combination of Quartz and Rubidium oscillator to meet the needs of the network. Each IOC qualifies the input signal and filters jitter and wander noise elements that may exist. In the event that all input references are lost or disqualified, the TimeProvider’s clock design, together with the SmartClock technology, goes into holdover mode with the oscillator providing the system reference.

The Rubidium IOC meets Stratum 2/Type II performance; the Quartz IOC meets Stratum 3E/Type I performance.

Operating Modes

You can configure the TimeProvider to operate in one of three modes: Synchronization Supply Unit (SSU), Subtending (SUB) as defined by Telcordia GR-378 Section 7, or Primary Reference Receiver (PRR) when the GPS input is available. Each mode is unique in its operation, and is defined in the following paragraphs.

SSU Mode

This is the TimeProvider’s default operating mode. You can select the system reference from any valid input on the PRS, INP1, INP2, or GPS connectors.

The GPS input operates as another input reference to the TimeProvider and is treated in the same manner as all other input references (PRS, INP1, or INP2). If the GPS input is active but later becomes disqualified, then the TimeProvider switches to the next available input reference according to the switching rules (Priority, SSM, etc.). If there are no other qualified inputs, then the TimeProvider enters the holdover state until an input is requalified.

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