Cabletron Systems 100BASE-FX, Cabling Manual

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Token Ring Media
9-16 Connector Types
The wires of the UTP cable must be organized in the RJ45 connector properly,
based upon the USOC specification and the IEEE 802.5 specification. This
organization of the wires at the connector is known as a pinout. The proper
pinout for the Token Ring RJ45 connector is given in Table 9-5.
The USOC specification orders the pairs in a four-pair cable into the pinout
shown in Figure 9-9, below. The RJ45 connector in the figure is being viewed from
the contact blade end, with the locking clip up. The contact blades of the RJ45
connector are numbered from left to right for purposes of identification.
Figure 9-9. USOC Pair Association
The EIA/TIA specifications, which are used in Ethernet environments, do not
match those of the USOC specification. The difference in the two specifications is
the arrangement of Pair 3 and Pair 4. While EIA/TIA cables may be used in an
IEEE 802.5 installation, they are not preferred. Although EIA/TIA cables will
function in a Token Ring environment, USOC cables will not function in an
Ethernet or FDDI TP-PMD environment. This is due to the usage of different wire
pairs by the different networking technologies.
BK RE GR OR
Pair 1
Pair 2
Pair 4
Pair 3
1845n22