Cisco Systems WSC3750X24TS specifications 100BASE-FX Ports, SFP Module Slots, 1-12

Chapter 1 Product Overview

10/100 and 10/100/1000 Ports

For information about Cisco IP Phones and Cisco Aironet Access Points, see the documentation that came with your IP phone or access point.

Note 100BASE-TX and 1000BASE-T traffic requires a Category 5 or later cable. 10BASE-T traffic can use Category 3 or Category 4 cables.

When you connect the switch to workstations, servers, routers, and Cisco IP Phones, be sure that the cable is a straight-through cable. When you connect 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 or later cable for proper operation. Pinouts for the cables are described in Appendix A, “Technical Specifications.”

You can use the mdix auto interface configuration command in the CLI to enable the automatic medium-dependent interface crossover (auto-MDIX) feature. When you enable the auto-MDIX feature, 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, no matter what type of device is 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 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 Mb/s 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 that are listed in Table B-1 on page B-3.

SFP Module Slots

Catalyst 3750 switches with SFP module slots support these SFP modules:

•100BASE-FX (MMF)

•1000BASE-BX

•1000BASE-LX

•1000BASE-SX

•1000BASE-ZX

Catalyst 3750 Switch Hardware Installation Guide

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