100Base-Fx Port; Sfp Module Slot - Cisco Catalyst 2940 Overview Manual

Front-Panel Description
When connecting the switch to a 1000BASE-T device, be sure to use a four twisted-pair, Category 5
Note
cable.
When connecting the switch to workstations, servers, and routers, be sure to use a twisted-pair
Note
straight-through cable. When connecting the switch to hubs or other switches, use a twisted-pair
crossover cable. Pinouts for the cables are described in
The 10/100/1000 port on the Catalyst 2940-8TT-S switch can be explicitly set to operate at full- or
half-duplex at 10 or 100 Mbps. The port is restricted to full-duplex mode when it is set at 1000 Mbps.
The port can also be set for speed autonegotiation, compliant with IEEE 802.3AB. In all cases, the cable
length from a switch to an attached device cannot exceed 328 feet (100 meters).

100BASE-FX Port

The 100BASE-FX port on the Catalyst 2940-8TF-S switch can use either 50/125- or 62.5/125-micron
multimode fiber-optic cabling. The 100BASE-FX port operates only at 100 Mbps in full-duplex mode.
In full-duplex mode, the cable length from the 100BASE-FX port to an attached device cannot exceed
6562 feet (2 kilometers).
You can use only the 100BASE-FX port or the SFP module slot at one time. When the switch is first
powered on, the 100BASE-FX port is enabled by default. However, if an SFP module is already installed
in the switch, the SFP module slot is enabled.
You can connect the 100BASE-FX port to an SC port on a target device by using one of the MT-RJ
fiber-optic patch cables listed in
cables that you need.
Table 1-2
Type
1-meter, MT-RJ-to-SC multimode cable
3-meter, MT-RJ-to-SC multimode cable
5-meter, MT-RJ-to-SC multimode cable

SFP Module Slot

The SFP module slot supports copper or fiber-optic SFP modules. The SFP module slot is numbered as
port 1.
Note You can use only the SFP module slot or the 100BASE-FX port at one time. When the switch is first
powered on, the 100BASE-FX port is enabled by default. However, if an SFP module is already installed
in the switch, the SFP module slot is enabled.
If you install an SFP module after the switch has powered on, you must reload the switch to enable the
SFP module.
Catalyst 2940 Switch Hardware Installation Guide
1-4
Table
MT-RJ Patch Cables for 100BASE-FX Connections
Appendix B, "Connectors and Cables."
1-2. Use the Cisco part numbers in
Cisco Part Number
CAB-MTRJ-SC-MM-1M=
CAB-MTRJ-SC-MM-3M=
CAB-MTRJ-SC-MM-5M=
Chapter 1 Overview
Table 1-2 to order the patch
OL-6157-01