28 CHAPTER 2: INSTALLING THE SWITCH
port, you need a cross-over cable. Many ports on workstations and
servers are configured as MDI (straight-through). If you want to make a
connection to an MDI port, you need to use a standard straight-through
cable. See Tabl e 7.
3Com recommends that you use Category 5 twisted pair cable — the
maximum segment length for this type of cable is 100 m (328 ft).
CAUTION: If you want to install the Switch using a Category 5E or
Category 6 cable, 3Com recommends that you briefly connect the cable
to a grounded port before connecting network equipment. If you do not,
the cables Electrostatic Discharge (ESD) may damage the Switch's port.
You can create a grounded port by connecting all wires at one end of a
UTP cable to an earth ground point, and the other end to a female RJ-45
connector located, for example, on a Switch rack or patch panel. The
RJ-45 connector is now a grounded port.
Tabl e 7 Cables required to connect the Switch 4200 Family to other devices if
auto-negotiation is disabled
Choosing the Correct
Fiber Cables
Choose from the following cable options:
■The 1000BASE-SX SFP ports can be connected to multimode fiber
cables only.
■The 1000BASE-LX and LH70 SFP ports can be connected to
single-mode fiber cables. The 1000BASE-LX SFP ports can also be
connected to multimode fiber cables using a conditioned launch
cable.
For detailed information on fiber cable specifications, refer to the
SuperStack 3 Implementation Guide that accompanies your Switch.
Cross-over Cable Straight-through Cable
Switch to Switch
(MDIX to MDIX) ✓✕
Switch to Hub
(MDIX to MDIX) ✓✕
Switch to PC (NIC)
(MDIX to MDI)
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