Instruction manual

ConneXium Ethernet Switches: 499NMS25101, 499NSS25101, 499NMS25102, 499NSS25102
31006003 01 July 2004 7
TP/TX Interface Link Control
The switches monitor the connected TP/TX line segments for short circuits and
interrupts. They use regular link test pulses in accordance with IEEE standard 802.3
for 10/100 base-T. The switch modules do not transmit any data to a TP/TX segment
from which they do not receive link test pulses.
Autopolarity Exchange
The switch automatically reverses polarity if the receive line pair is incorrectly
connected (when RD+ and RD- are switched).
Autocrossing
The switch detects the transmit and receive pairs (MDI, MDI-X). It automatically
configures its port for the correct transmit and receive pins. Consequently, it does
not matter whether you connect devices using a crossover or straight cable.
F/O Interface Link Control
The 499NMS2510x and 499NSS2510x modules monitor the connected F/O line for
interrupts using idle signals during frame pauses (in accordance with IEEE standard
802.3 100 base-FX). These modules transmit data only to F/O lines from which they
receive idle signal(s).
If the optical input power decreases below the low light threshold, the transmit and
receive path is disabled for data and the idle signal is transmitted.
Far-End Fault
The optical transmission distance(s) of the 499NMS2510x and 499NSS2510x
modules can be monitored in the receiving direction as well as in the transmitting
direction if the other side also supports far-end fault. If both sides do not support far-
end fault, the optical transmission distance is monitored only in receiving direction.
The far-end fault is sent if the optical input power at the optical port has fallen under
the low light level. If far-end fault is received, the link becomes inactive (the ACT/
LNK LED is off).
Note: An unpopulated connection is assessed as a line interrupt. The TP/TX line
to any terminal equipment that has been switched off is also assessed as a line
interrupt since a de-energized bus coupler cannot transmit link test pulses.