4
Loopback Type (DIP Switch S1, Position 2)
This switch identifies which data line is looped back when the Loopback DIP switch is
enabled. The data line loopback selection can specify either a Fiber Loopback or a
Coax Loopback.
By default this feature is
COAX
.
This feature can be controlled by SNMP management software (iView
2
) when the
HOST iMcV-DS3/E3-LineTerm module is installed in a managed chassis.
Fault Loopback (DIP Switch S1, Position 4)
This switch enables or disables the Fault Loopback feature. A normal fault (LOS) will
cause an Alarm Indication Signal (AIS) to be sent on to the next line segment. This
feature provides for a fault condition to be sent back towards the direction of the
detected fault. In this way, both upstream and downstream craft personnel are
alerted to a single fault.
The Fault Loopback feature uses the iMcV-DS3/E3-LineTerm module LEDs to
indicate that a loss of one strand of fiber has occurred. When a strand becomes
unavailable, the module at the receiver-end detects the “LOS” of the fiber link and
lights the LOS LED. The module then responds by sending a Remote Alarm
Indication (RAI) signal back to the Fiber line turning ON the RAI LED at the far end of
the line and sending AIS to the COAX Port. The RAI LED is now ON at the source of
the Fiber fault. By using the Fault Loopback Function, 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 M13 framed all-ones signal for DS3. For E3 and STS-1,
the AIS signal is an unframed all-ones pattern.
By default this feature is
ENABLED
.
This feature can be controlled by SNMP management software (iView
2
) when the
HOST iMcV-DS3/E3-LineTerm module is installed in a managed chassis.
Transmit LIU Waveshape (Line Build-Out) (DIP Switch S1, Position 5)
This switch selects the optimal transmit waveshape for the line build-out distance on
the coax line. The transmit waveshape can be set for a distance of either 0 to 255
feet or over 255 feet. This feature corrects problems related to cabling (i.e., cross-
talk, electromagnetic interference, etc). Improperly setting this switch will cause
signal degradation.
By default this feature is set to
0 to 255 FEET
(450 ft maximum).
