Black Box Mixed-Media Fiber Hubs
Installation and User Guide (4/99)
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When using single-mode fiber cable, be sure to use single-mode fiber port
connectors. Single-mode fiber cable has a smaller diameter than multi-mode fiber cable (9/125
microns for single-mode, 50/125 or 62.5/125 microns for multi-mode where xx/xx are the
diameters of the core and the core plus the cladding respectively). Single-mode fiber allows full
bandwidth at longer distances, and may be used to connect 10 Mbps nodes up to 10 Km apart,
or 15Km with the SPM in an LH8050A-SSCSM.
The same procedures as for multi-mode fiber applies to single-mode fiber connectors. Follow
the steps listed in Section 3.3 and 3.4 above.
3.6
Connecting Twisted Pair (RJ-45,CAT3, CAT5, Unshielded or Shielded)
The RJ-45 ports of the LH8050A Dual-Speed Fiber Hubs can be connected to the
following two media types: 100BASE-TX and 10BASE-T. CAT 5 cables should be used when
making 100BASE-TX connections. When the ports are used as 10BASE-T ports, CAT 3 may
be used. In either case, the maximum distance for unshielded twisted pair cabling is 100 meters
(328 ft).
Media
IEEE Standard Connector
Twisted Pair (CAT 3, 4, 5) 10BASE-T RJ-45
Twisted Pair (CAT 5)
100BASE-TX RJ-45
NOTE :
It is recommended that high quality CAT. 5 cables (which work for both 10 Mbps
and 100Mbps ) be used whenever possible in order to provide flexibility in a mixed-
speed network, since dual-speed ports are auto-sensing for either 10 and 100Mbps .
The following procedure describes how to connect a 10BASE-T or 100BASE-TX
twisted pair segment to the RJ-45 port. The procedure is the same for both unshielded
and shielded twisted pair cables.
1. Using standard twisted pair media, insert either end of the cable with an RJ-45 plug into
the RJ-45 connector of the port. Note that, even though the connector is shielded, either
unshielded or shielded cables and wiring may be used.
2. Connect the other end of the cable to the corresponding device
3. Use the LINK LED to ensure proper connectivity by noting that the LED will be
illuminated when the unit is powered and proper connection is established
4. For Port #1, if the LINK LED is not illuminated, change to port 1X. If this does not
help, ensure that the cable is connected properly and that the device on the other end is
powered on and is not defective.
3.6.1 100Mbps Collision Domain Diameter, Cable Distances and PDV Calculations
