100Base-Fx Ports; Sfp Module Slots - Cisco Catalyst 3750 Hardware Installation Manual

10/100 and 10/100/1000 Ports
100BASE-TX and 1000BASE-T traffic requires Category 5 cable. 10BASE-T traffic can use Category 3
Note
or Category 4 cables.
When connecting the switch to workstations, servers, routers, and Cisco IP Phones, be sure that the cable
is a straight-through cable. When connecting the switch to switches or hubs, use a crossover cable. When
using a straight-through or crossover cable for 1000BASE-T connections, be sure to use a twisted
four-pair, Category 5 cable for proper operation. Pinouts for the cables are described in
"Technical Specifications."
You can use the mdix auto interface configuration command in the CLI to enable the automatic
Note
medium-dependent interface crossover (auto-MDIX) feature. When the auto-MDIX feature is enabled,
the switch detects the required cable type for copper Ethernet connections and configures the interfaces
accordingly. Therefore, you can use either a crossover or a straight-through cable for connections to a
copper 10/100, 10/100/1000, or 1000BASE-T SFP module port on the switch, regardless of the type of
device on the other end of the connection.
The auto-MDIX feature is enabled by default on switches running Cisco IOS Release 12.2(18)SE or
later. For releases between Cisco IOS Release 12.1(14)EA1 and 12.2(18)SE, the auto-MDIX feature is
disabled by default. For configuration information for this feature, see the switch software configuration
guide or the switch command reference.
Many legacy powered devices, including older Cisco IP phones and access points that do not fully
Note
support IEEE 802.3af, might not support PoE when connected to the switches by a crossover cable.

100BASE-FX Ports

The 100BASE-FX ports use 50/125- or 62.5/125-micron multimode fiber-optic cabling. In full-duplex
mode, the cable length from a switch to an attached device cannot exceed 6,562 feet (2 kilometers).
The 100BASE-FX ports operate only at 100 Mbps in either full- or half-duplex mode and do not support
autonegotiation. The half-duplex mode is the default setting.
You can connect a 100BASE-FX port to an SC or ST port on a target device by using one of the MT-RJ
fiber-optic patch cables listed in

SFP Module Slots

Catalyst 3750 switches with SFP module slots support these SFP modules:
•
•
•
•
•
Catalyst 3750 Switch Hardware Installation Guide
1-12
100BASE-FX (MMF)
1000BASE-BX
1000BASE-LX
1000BASE-SX
1000BASE-ZX
Table B-1 on page B-3.
Chapter 1 Product Overview
Appendix A,
OL-6336-06