Cisco Catalyst 3550

B-3
Catalyst 3550 Multilayer Switch Hardware Installation Guide
78-11358-03
Appendix B Connector and Cable Specifications
Connector Specifications
10/100 Ports
The 10/100 Ethernet ports use standard RJ-45 connectors and Ethernet pinouts
with internal crossovers, as shown by an X in the port name. These ports have the
transmit (TD) and receive (RD) signals internally crossed so that a twisted-pair
straight-through cable and adapter can be attached to the port. Figure B-2 shows
the pinout.
When connecting 10/100 ports to compatible devices, such as servers,
workstations, and routers, you can use a two or four twisted-pair, straight-through
cable wired for 10BASE-T and 100BASE-TX. Figure B-7 shows the two
twisted-pair, straight-through cable schematics. Figure B-9 shows the four
twisted-pair, straight-through cable schematics.
When connecting the ports to other devices, such as switches or repeaters, you can
use a two or four twisted-pair, crossover cable. Figure B-8 shows the two
twisted-pair, crossover cable schematics. Figure B-9 shows the four twisted-pair,
crossover cable schematics.
You can use Category 3, 4, or 5 cabling when connecting to
10BASE-T-compatible devices. You must use Category 5 cabling when
connecting to 100BASE-TX-compatible devices.
Note Use a straight-through cable to connect two ports only when one port is
designated with an X. Use a crossover cable to connect two ports when both ports
are designated with an X or when both ports do not have an X.