10/100 And 10/100/1000 Ports - Cisco ME-C3750-24TE-M Hardware Installation Manual

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10/100 and 10/100/1000 Ports

Note
Note
Catalyst 3750 Switch Hardware Installation Guide
2-6
You can set the 10/100 on the switch to operate in any combination of half duplex,
full duplex, 10 Mbps or 100 Mbps. You can set the 10/100/1000 ports to operate
in 10 Mbps, 100 Mbps, or 1000 Mbps in full duplex. You can also set these ports
for speed and duplex autonegotiation in compliance with IEEE 802.3ab. (The
default setting is autonegotiate.) When set for autonegotiation, the port senses the
speed and duplex settings of the attached device and advertises its own
capabilities. If the connected device also supports autonegotiation, the switch port
negotiates the best connection (that is, the fastest line speed that both devices
support and full-duplex transmission if the attached device supports it) and
configures itself accordingly. In all cases, the attached device must be within 328
feet (100 meters).
100BASE-TX and 1000BASE-T traffic requires Category 5 cable. 10BASE-T
traffic can use Category 3 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 Appendix B, "Connector and Cable Specifications."
On switches running Cisco IOS Release 12.1(14)EA1 or later, you can use the
mdix auto command in the CLI to enable the automatic crossover feature. When
the automatic crossover 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 or 10/100/1000 port on the switch, regardless the
type of device on the other end of the connection.
The automatic crossover feature is disabled by default. For configuration
information for this feature, refer to the switch software configuration guide or the
switch command reference.
Chapter 2 Product Overview
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