363-206-285
Circuit Pack Descriptions
Issue 3 June 2001
7-115
Timing Circuitry 7
Each TG circuit pack sends timing signals to each OLIU. Each OLIU monitors the
timing inputs from both TG circuit packs. The 22D-U OLIU normally selects the
timing signals from the active TG. Each OLIU provides timing signals derived from
the incoming optical signal to both TG circuit packs for line (formerly loop) timing
and DS1 timing outputs (BITS).
Protection Circuitry 7
Optional 1+1 nonrevertive unidirectional line protection switching compliant with
SONET specifications is provided. The 22D-U OLIU is protection switched by the
SYSCTL in response to an external command, incoming signal failure, or internal
equipment fault. The 22D-U OLIU circuit pack is protection switched with the
optical line.
The 22D-U OLIU circuit pack interfaces with STS-1 signals from the circuit packs
in the main and function unit slots and selects the signals from the service or
protection slot of each pair as directed by the SYSCTL.
The 22D-U OLIU provides selectors for timing signals from the TG circuit packs.
The 22D-U OLIU monitors these inputs and can autonomously select either one.
The SYSCTL can inhibit autonomous selection and make its own selection.
Fault Detection Circuitry 7
The 22D-U OLIU circuit pack has in-service and out-of-service built-in test
capability. In-service testing is continuous and errors are reported when they
occur to the SYSCTL via the intra-shelf control bus. An out-of-service test is
performed whenever the OLIU circuit pack is inserted or recovers from a transient
failure.
The 22D-U OLIU has provisionable VT signal degrade and STS signal degrade
BER threshold capabilities for path protection switching.
Performance Monitoring 7
The 22D-U OLIU provides PM circuitry for the following performance parameters:
â– Section SEFS count
â– Line parameters based on B2 coding violations.
To Next Page
Loading...
Need help?
General
