Contemporary Control Systems EISC Configurable Switches User Manual - Manual (Page 29)

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7.2.10
Port Signal Strength
The EISC can display the signal strength received at its RJ-45 ports in four graduated
steps. Each port display can thereby indicate the robustness of its communication
channel. Although an attached device could cause problems, the usual concern with
signal strength is the nature of
attached twisted-pair cable.
A port label will only display as
active if it is receiving proper
Link Pulses. If a port is not
attached to a working partner,
its label will be dim and its bar
graph completely gray.
To read the display properly,
the user must have knowledge
of the cabling attached to the
EISC. As more cable length is
used to connect an EISC port
to a remote device, weaker
signal strength will be seen.
As the 100-m cable length limit
is approached, the smallest
signal strength step will be
displayed in red (as with Port
11 in Figure 32). A disparity
between two ports does not
necessarily imply a problem
with the weaker one; the two
ports may simply be attached
to different lengths of cable.
Figure 32 — Twisted-Pair Signal Strength
Example: In Figure 32, a comparison of Port 10 and Port 11 should only be interpreted
as problematic if the segment lengths for Ports 10 and 11 are approximately equal. On
the other hand, if Port 10 has only 15 m of attached cable while Port 11 has 85 m of
attached cable, the example display would be normal.
Note: There is no requirement for all segments of a trunk to be equal in length. Thus,
Ports 9–12 in Figure 32, could be displaying a properly functioning trunk.
Note for
12-port models: The signal strength display applies only to Ports 1–8. For
Ports 9–12 the bar graph will be completely blank — even if the port is working.
Although there is no signal strength indication for Ports 9–12, the status of these ports
can be determined by simply observing the port label . If the label is not dimmed, the
port is active. But if the label is dimmed, the port is not in use.
(Only for 100 Mbps RJ-45 ports)