Cisco 3750G-12S - Catalyst Switch - Stackable Hardware Installation Manual page 78

Connecting to the 10/100 and 10/100/1000 Ports
Table 2-1
Device
Switch to switch
Switch to hub
Switch to computer
or server
Switch to router
Switch to IP phone
1. 100BASE-TX and 1000BASE-T traffic requires twisted four-pair, Category 5 or higher
cable. 10BASE-T traffic can use Category 3 or Category 4 cable.
You can use the mdix auto interface configuration command in the CLI to enable the automatic
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.
Follow these steps to connect to 10BASE-T, 100BASE-TX or 1000BASE-T devices:
PoE faults are caused when noncompliant cabling or powered devices are connected to a PoE port. Only
Caution
standard-compliant cabling can be used to connect Cisco pre-standard IP Phones and wireless access
points or IEEE 802.3af-compliant devices to PoE ports. A cable or device that causes a PoE fault must
be removed from the network.
Step 1 When you connect the switch to workstations, servers, routers, and Cisco IP Phones, connect a
straight-through cable to an RJ-45 connector on the front panel. (See
the switch to other switches or to repeaters, use a crossover cable. (See the
Specifications" section on page B-5
When you connect a switch to 1000BASE-T-compatible devices, be sure to use a twisted four-pair,
Category 5 or later cable.
You can connect the Catalyst 3750 switch to a Cisco IP Phone through a straight-through, twisted
four-pair Category 5 or later cable. The rear panel of the Cisco IP Phone might have more than one RJ-45
connector. Use the LAN-to-phone connector to connect the Cisco IP phone to the switch. See the Cisco
IP Phone documentation for more information about connecting devices to it.
Note
Catalyst 3750 Switch Hardware Installation Guide
2-40
Recommended Ethernet Cables
Crossover Cable
Yes
Yes
No
No
No
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.
1
Straight-Through Cable
No
No
Yes
Yes
Yes
for cable-pinout descriptions.)
Chapter 2 Switch Installation
1
Figure 2-55.) When you connect
"Cable and Adapter
OL-6336-10