Fault Loopback
This switch enables or disables the Fault Loopback feature on the copper port. A normal copper line LOS fault will cause a Remote Alarm Indictor (RAI) to be sent on to the fiber line segment causing the normal AIS to be sent on the far end copper port. The fault loopback feature provides for a fault indication to be sent back to the copper line as an AIS signal. In this way, both upstream and downstream personnel are alerted to a copper cable fault.
The Fault Loopback feature is always active on the fiber line. When a fiber line becomes unavailable, the module detects the LOS on the fiber link and lights the LOS LED. The module then sends AIS to the local copper port and sends a RAI signal back to the fiber. The far end unit turns ON the RAI LED and outputs AIS to the far end copper line. With this, a local site administrator can quickly determine where a fiber fault is located from either end of the fiber line.
The AIS is transmitted as an unframed all ones pattern on the copper port.
The default loopback DIP Switch is disabled by default.
This feature can be controlled by
Transmit LIU Waveshape and Gain (Line Build-Out)
This group of switches can be configured for the length of line the unit is driving, from 0 feet to a maximum of 655 feet. For longer length lines, the unit can be configured for CSU signal gain to address
By default this feature is set to 0 to 133 feet line Buildout for DSX1 lines.
Transmit Data Source
These switches select the transmit mode used by the
•Standard data
•Unframed All Ones (diagnostic)
•Alternating Ones and Zeros (diagnostic)
•Pseudorandom Bit Sequence Pattern for T1 and
These standard Telco transmission pattern modes are provided to help diagnose transmission errors in the line.
By default this feature is set to Standard Data.
This feature can be controlled by
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