GarrettCom DS8016 Manual De Usuario
Magnum DS8016 Dual-Speed Stackable Hubs Installation and User Guide (07/06)
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3.2.1
Connecting Twisted Pair (RJ-45, CAT 3 or CAT 5, Unshielded or
Shielded)
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.
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
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 and is not defective.
is powered and is not defective.
3.2.2
Attaching to the MII port in the rear
MII Transceivers may be attached here. Since there are no industry standards for these,
interoperability of user-selected MII transceivers that may be attached to a DS8016’s MII
port cannot be assured. Use of the MII port is not normally recommended accordingly.
port cannot be assured. Use of the MII port is not normally recommended accordingly.
3.2.3
100Mbps Collision Domain Diameter, Cable Distances and PDV
Calculations
The 100Mbps Collision Domain Diameter is the length of the longest path
between any two devices in a single collision domain. A collision domain is defined as a
cluster of network devices which are connected by means of a repeater or repeaters such that
no bridging devices are present between any two devices in the cluster. In order to install an
IEEE 802.3u compliant Fast Ethernet network, the collision domain . . regardless of the
actual network topology . . must be less than 512 BT (Bit Times). Bit Times are related to
media type as shown in Table 3.2.3a.
Table 3.2.3a: Worst case round-trip delay for Fast Ethernet media*
Media Type
Round-trip delay in
Bit Time per Meter (BT/m)
Fiber Optic
1.000
Shielded TP cable
1.112
Category 5 Cable
1.112
Category 3, 4 Cable
1.140
*Worst case delays taken from IEEE Std 802.3u-1995, actual delays may be less for a particular cable.
Contact your cable supplier for exact cable specifications.
Contact your cable supplier for exact cable specifications.
Each Fast Ethernet device component also has an associated BT delay which
depends on the physical signaling system employed. Table 3.2.3b shows each Fast Ethernet