The 10/100/1000 Ethernet ports on Catalyst 2950T-24, Catalyst 2950T-48-SI, and Catalyst 2950 Long-Reach Ethernet (LRE) switches use standard RJ-45 connectors. Figure B-2 shows the pinout.

Note - On the Catalyst 2950 LRE switches, the four input uplink ports are bundled as two logical ports, each consisting of a copper 10/100/1000 port and a fiber-optic small form-factor pluggable (SFP) module slot, respectively.

Within each logical port, you can use only the copper or the fiber-optic port at one time. If the Catalyst 2950 LRE switch senses more than two connections for both logical ports, the switch chooses the fiber-optic connections over the copper connections in default operation.

See the "SFP Module Slots" section for more information on LRE uplink logical ports.

Connecting to 10BASE-T and 100BASE-TX Devices
When connecting the ports to 10BASE-T and 100BASE-TX devices, such as servers, workstations, and routers, you can use a two or four twisted-pair, straight-through cable wired for 10BASE-T and100BASE-TX. Figure B-10 shows the two twisted-pair, straight-through cable schematics. Figure B-12 shows the four twisted-pair, straight-through cable schematics.

When connecting the ports to 10BASE-T- and 100BASE-TX devices, such as switches or repeaters, you can use a two or four twisted-pair, crossover cable. Figure B-11 shows the two twisted-pair, crossover cable schematics. Figure B-13 shows the four twisted-pair, crossover cable schematics.

You can use Category 3, 4, or 5 cabling when connecting to 10BASE-T devices. You must use Category 5 cabling when connecting to 100BASE-TX devices.

Connecting to 1000BASE-T Devices
When connecting the ports to 1000BASE-T devices, such as servers, workstations, and routers, you must use a four twisted-pair, Category 5, straight-through cable wired for 10BASE-T, 100BASE-TX, and 1000BASE-T. Figure B-14 shows the straight-through cable schematics.

When connecting the ports to other devices, such as switches or repeaters, you must use a four twisted-pair, Category 5, crossover cable. Figure B-15 shows the crossover cable schematics.

Note - Be sure to use a four twisted-pair, Category 5 cable when connecting to a 1000BASE-T device.sd

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.

Figure B-2 - RJ-45 Pinouts for 10/100/1000 and 1000BASE-T GBIC Module Ports