Cisco 3550 - Manual (Page 48)

2-18
Catalyst 3550 Switch Hardware Installation Guide
OL-6155-01
Chapter 2 Switch Installation
Powering the Switch and Connecting Devices
The switch 10/100 and 10/100/1000 port default setting is autonegotiate. If the attached device does not
support autonegotiation, you can explicitly set the speed and duplex parameters. After connecting the
cable, the port LED turns green when both the switch and the connected device have established a link.
Connecting to the 10/100 Inline Power Ports
You can connect the Catalyst 3550-24PWR switch to a Cisco IP Phone through a straight-through,
twisted four-pair Category 5 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 IP phone to the Catalyst 3550-24PWR
switch.
You can configure the 10/100 ports on the Catalyst 3550-24PWR switch to either automatically provide
inline power when a Cisco IP Phone or a Cisco Aironet Access Point is connected or to never provide
inline power even if an IP phone or an access point is connected. The default setting is Auto.
Warning Voltages that present a shock hazard can exist on inline power circuits if interconnections are made
by using uninsulated exposed metal contacts, conductors, or terminals. Avoid using such
interconnection methods unless the exposed metal parts are in a restricted access location and users
and service people who are authorized to access the location are made aware of the hazard. A
restricted access area can be accessed only through the use of a special tool, lock and key, or other
means of security. Statement 1072
Caution It takes a Catalyst 3550-24PWR 10/100 port up to 10 seconds to initially detect, power up, and link to a
Cisco IP Phone. If you disconnect the Cisco IP Phone before link is established, you must wait 10
seconds before connecting another network device (other than another IP phone) to that switch port.
Failure to do so can result in damage to that network device.
You also can connect the Cisco IP Phone or Cisco Aironet Access Point to a Catalyst 3550-24PWR
10/100 port and to an AC power source for redundant power. The power source to which the external
device is first connected becomes its primary power source, and the second power source is its backup.
If the primary source fails, the second power source becomes the primary power source to the device.
During the power transfer, the device might reboot or reestablish link with the switch.
For information about Cisco IP Phones and Cisco Aironet Access Points, see the documentation that
came with your IP phone or access point.
Connecting to 100BASE-FX Ports
Caution To prevent ESD damage, follow your normal board and component handling procedures when
connecting to the 100BASE-FX ports.
The 100BASE-FX ports operate only at 100 Mbps and support both full- and half-duplex mode. The
half-duplex mode is the default setting. Autonegotiation is not supported.
To connect to a 100BASE-FX port, remove the rubber plug from the port and the rubber cap from the
MT-RJ patch cable. Store for future use. Insert the cable in the port, and insert the other cable end in an
SC or ST connector on the target device. The port LED turns green when both the switch and the
connected device have established a link.