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Catalyst 3750-X and 3560-X Switch Hardware Installation Guide
OL-19593-01
Chapter 2 Switch Installation
Connecting Devices to the Ethernet Ports
10/100/1000 Ethernet Port Connections
The 10/100/1000 Ethernet ports use RJ-45 connectors with Ethernet pinouts. The maximum cable length
is 328 feet (100 meters). The 100BASE-TX and 1000BASE-T traffic requires Category
5, Category 5e,
or Category
6 UTP cable. The 10BASE-T traffic can use Category 3 or Category 4 cable.
The autonegotiation feature is enabled by default on the switch. At this setting, the switch ports
configure themselves to operate at the speed of attached device. If the attached device does not support
autonegotiation, you can explicitly set the switch port speed and duplex parameters. To maximize
performance, either let the ports autonegotiate both speed and duplex, or set the port speed and duplex
parameters on both ends of the connection.
For simplified cabling, the automatic medium-dependent interface crossover (auto-MDIX) feature is
enabled by default on the switch. With auto-MDIX enabled, the switch detects the required cable type
for copper Ethernet connections and configures the interface accordingly. Therefore, you can use either
a crossover or a straight-through cable for connections to a switch 10/100/1000 Ethernet port regardless
of the type of device on the other end of the connection.
See the switch software configuration guide or the switch command reference on Cisco.com for more
information about enabling or disabling autonegotiation and auto-MDIX.
If auto-MDIX is disabled, use the guidelines in Table 2-3 to select the correct cable for connecting the
switch 10/100/1000 Ethernet ports to other devices. See the “Cable and Adapter Specifications” section
on page B-5 for cable-pinout descriptions.
PoE+ Port Connections
The 10/100/1000 PoE ports have the same autonegotiation settings and cabling requirements that are
described in the
“10/100/1000 Ethernet Port Connections” section on page 2-28. These ports can provide
PoE or PoE+ inline power.
PoE inline power supports devices compliant with the IEEE 802.3af standard, as well as prestandard
Cisco IP Phones and Cisco Aironet Access Points. Each port can deliver up to 15.4 W of PoE.
PoE+ inline power supports devices compliant with the IEEE 802.3at standard, by delivering up to 30 W
of PoE+ power per port to all switch ports.
See Table 1-17 on page 1-18 for the power supply modules required to support PoE and PoE+ on 24- and
48-port switches.
To access a PoE planning tool, use the Cisco Power Calculator available on Cisco.com:
http://tools.cisco.com/cpc/launch.jsp
Ta b l e 2-3 Recommended Ethernet Cables (When Auto-MDIX is Disabled)
Device Crossover Cable
1
1. 100BASE-TX and 1000BASE-T traffic requires twisted four-pair, Category 5, Category 5e, or
Category 6 cable. 10BASE-T traffic can use Category 3 or Category 4 cable.
Straight-Through Cable
1
Switch to switch Yes No
Switch to hub Yes No
Switch to computer or server No Yes
Switch to router No Yes
Switch to IP phone No Yes
