3.8.2
Connecting Fiber Optic ST-type, “twist-lock”
The following procedure applies to installations using ST-type fiber connectors. This
procedure applies to ports using multi-mode ST fiber connectors.
1. Before connecting the fiber optic cable, remove the protective dust caps from the
tips of the fiber connectors. Save these dust caps for future use.
2. Wipe clean the ends of the dual connectors with a soft cloth or lint-free lens tissue
dampened in alcohol. Make certain the connectors are clean before connecting.
Note:
One strand of the duplex fiber optic cable is coded using color bands at
regular intervals; you must use the color-coded strand on the associated ports at
each end of the fiber optic segment.
3.
Connect the Transmit (TX) port (light colored post) on the fiber port to the Receive (RX)
port of the remote device. Begin with the color-coded strand of the cable for this first
TX-to-RX connection.
4.
Connect the Receive (RX) port (dark colored post) to the Transmit (TX) port of the
remote device. Use the non-color coded fiber strand for this.
5.
The LINK LED on the front of the fiber connector will illuminate when a proper
connection has been established at both ends (and when power is ON in the unit). If
LINK is not lit after cable connection, the normal cause is improper cable polarity. Swap
the fiber cables at the fiber connector to remedy this situation.
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3.8.3
Power Budget Calculations for PXES6P Series, Fiber Media
Receiver Sensitivity and Transmitter Power are the parameters necessary to compute
the power budget. To calculate the power budget of different fiber media installations using
PXES6P Switches, the following equations should be used:
OPB (Optical Power Budget) = P
T
(min) - P
R
(min)
where P
T
= Transmitter Output Power, and P
R
= Receiver Sensitivity
Worst case OPB = OPB - 1dB(for LED aging) - 1dB(for insertion loss)
Worst case distance = {Worst case OPB, in dB} / [Cable Loss, in dB/Km]
where the “Cable Loss” for 62.5/125 and 50/125
μ
m
(m.m.) is 2.8 dB/km,
and the “Cable Loss” for 100/140 (Multi-mode) is 3.3 dB/km,
and the “Cable Loss” for 9/125 (Single-mode) is 0.5 dB/km
and the “Cable Loss” for 9/125 (Single-mode) is 0.25 dB/km (SSCX)
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* Note: The use of either multi-mode fiber to operate at 100Mbps speed over long distances
(i.e., over approx. 400 meters) can be achieved
only
if the following factors are both applied:
•
The 100Mb fiber segment must operate in full-duplex (FDX) mode, and
•
The worst-case OPB of the fiber link must be greater than the fiber cable’s passive
Attenuation.
(Attenuation = Cable loss + LED aging loss + Insertion loss + safety factor)
3.8.6
Connections to NICs which support Auto-Negotiation, RJ-45 ports
The copper ports of PXES6P-Series Switches will function properly with NICs
(Network Interface Cards) which support Auto-Negotiation, and the Fast Link Pulse (FLP)
coding for the 100BASE-TX signaling system. When connecting a NIC to the PXES6P Series, it
may be necessary to reload the NIC drivers on the user device if the NIC has been
communicating with a protocol other than 100BASE-TX (such as 10BASE-T). When 100Mb
operation is agreed and in use, the 10/100 LED is illuminated steady ON and is OFF, if 10 Mbps
traffic.
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