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7 Connect to the Switch Ports
This section describes how to connect to the fixed switch ports and to the 10-Gigabit Ethernet module
slots.
Connect to 10/100/1000 Ports
The 10/100/1000 Ethernet ports use standard 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 devices. If the attached device does not
support autonegotiation, you can explicitly set the switch port speed and the 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.
Connect to 10/100/1000 PoE Ports
The 10/100/1000 PoE ports have the same default settings and cabling requirements that are described
in the previous section.
The PoE ports provide PoE support for devices compliant with IEEE 802.3af and also provide Cisco
pre-standard PoE support for Cisco IP Phones and Cisco Aironet Access Points.
Each port can deliver up to 15.4 W of PoE. With the 1150-W power supply module, the
Catalyst 3750E-48PS switch can deliver 15.4 W on all 48 ports. With the 750-W power supply
module, the switches can deliver 15.4 W of PoE on any 24 of the 48 ports, or any combination of the
ports can deliver an average of 7.7 W of PoE at the same time, up to a maximum switch power output
of 370 W. On a per-port basis, you can control whether or not a PoE port automatically provides
power when an IP phone or an access point is connected.
See the hardware installation guide on Cisco.com for more information about the switch power supply
options.