Installation guide

2-7
Catalyst 3550 Multilayer Switch Hardware Installation Guide
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Chapter 2 Product Overview
Front-Panel Description
The default setting is autonegotiate. At this setting, 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.
10/100 Inline Power Ports
The 10/100 ports on the Catalyst 3550-24PWR switch provide protocol support
for Cisco IP Phones and Cisco Aironet Access Points:
• Provide –48 VDC power to all Cisco IP Phones and Cisco Aironet Access
Points
• Automatically detect a Cisco IP Phone or an access point that is connected
On a per-port basis, you can control whether or not a Catalyst 3550-24PWR
10/100 port automatically provides power when an IP phone or an access point is
connected. There are two inline power settings for each 10/100 port: Auto and
Never. When you select the Auto setting for inline power on a port, the port only
provides power if an IP phone or an access point is connected to it. The Auto
setting is the default. However, when you select the Never setting for inline power
on a port, the port does not provide power even if a Cisco IP phone or an access
point is connected to it.
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 Mbps 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 listed in Table B-1 on page B-3.