Reference Input Signals; Selecting The Input - Symmetricom TimeProvider 1000 User Manual

Chapter 1 Overview of the TimeProvider

Reference Input Signals

Reference Input Signals
The Input module accepts one or two E1, 2.048 MHz analog, 1.544 MHz or 6.312
MHz analog (Japan-specific), T1, and Composite Clock (including JCC and JCC4)
inputs on ports INP1 and INP2. The CC inputs are used solely for Subtending
mode; if you provision INP1 or INP2 to a CC type, then Subtending mode is
automatically enabled. You can also connect a 2.048, 5, or 10 MHz or
Japan-specific 1.544 MHz or 6.312 MHz input reference signal on the PRS port.
The TimeProvider accepts full-level signals or bridged signals (–20 dB); the inputs
are terminated per G.703. You can also connect a GPS antenna via the
TimeProvider Interface Unit (TPIU) to the GPS Input port on the shelf.
Make the input connections using the procedures described in
Connections, on page 57, then provision the inputs using the software commands
described in
Input State
You can provision each input to one of three states:
Disabled – the input is not used
Monitor – the system monitors the input for signal faults and performance data,
but it cannot be selected as the system reference
Enabled – the system monitors the input for signal faults and performance data.
The input can be selected as the system reference in SSU or SUB mode or as a
backup reference in PRR mode.

Selecting the Input

Many considerations influence which system reference you choose:
SSM or User-assigned Quality Level
User-assigned Priority Level
Switching mode
User-assigned Input State
Active alarms on an input
You can provision the TimeProvider to automatically select the highest-quality input
based on priority and performance qualification, or you can manually select the
input signal you want to use. If that signal becomes disqualified for any reason, the
local oscillator goes into the Holdover mode.
32 TimeProvider User's Guide
Provisioning the Input Reference, on page 99.
097-58001-02 Revision C – August 2005
Making Input