A-6
Technical Specifications
A.5 CROSSOVER WIRING
Two ELS10-26s can communicate only if the transmitter on one
unit is connected to the receiver on the other unit. This reversal, or
crossover function, can be implemented either in the wiring or in
the device itself. When connecting ELS10-26s, a crossover must be
implemented in the wiring. Refer to Table A-5 for crossover pin
assignments.
A.6 5 - 4 - 3 RULE
Between any two nodes (i.e., PCs or other stations) on the network,
there can be:
• Up to five segments in series
• Up to four repeaters or multi-port hubs
• Up to three populated segments (that is, segments attached to
two or more PCs). The remaining two segments are
unpopulated; these are known as inter-repeater links or IRLs.
This distinction between populated and unpopulated segments
is significant for coax networks only.
Table A-5. Crossover RJ45 Pin Assignments
ELS10-26 ELS10-26
1 (Rx+) 3 (Tx+)
2 (Rx-) 6 (Tx-)
3 (Tx+) 1 (Rx+)
6 (Tx-) 2 (Rx-)
Note: This rule is completely consistent with the IEEE 802.3
specification, and is meant only to summarize the configuration
specification.