Connecting To 1000Base-T Devices; Lre Port - Cisco WS-C2950T-48-SI Hardware Installation Manual

Appendix B Connectors and Cables

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.
When connecting the ports to other devices, such as switches or repeaters, you must use a four
twisted-pair, Category 5, crossover cable.
Be sure to use a four twisted-pair, Category 5 cable when connecting to a 1000BASE-T device.
Note
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

LRE Port

The LRE port uses a single 50-pin RJ-21 connector, as shown in
pins. Because the Catalyst 2950ST-24 LRE and Catalyst 2950ST-24 LRE 997 switches use 48 pins, pin
25 on the top row and pin 50 on the bottom row are not used
The Catalyst 2950ST-8 LRE switch uses 16 pins. Pins 9 through 25 on the top row and pins 34 through
50 on the bottom row are not used.
Figure B-3
OL-6156-01
Figure B-14 shows the straight-through cable schematics.
RJ-45 Pinouts for 10/100/1000 and 1000BASE-T GBIC Module Ports
Pin Label
1 TP0+
2 TP0-
3 TP1+
4 TP2+
5 TP2-
6 TP1-
7 TP3+
8 TP3-
RJ-21 Connector
25 9
50 34
Figure B-15 shows the crossover cable schematics.
1 2 3 4 5 6 7 8
Figure
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Catalyst 2950 Switch Hardware Installation Guide
Connector Specifications
B-3. Each LRE port uses two
B-3