Installation guide

Chapter 1 Product Overview
Front Panel Description
1-12
Catalyst 3750 Switch Hardware Installation Guide
OL-6336-01
Warning Voltages that present a shock hazard may exist on Power over Ethernet (PoE)
circuits if interconnections are made using uninsulated exposed metal
contacts, conductors, or terminals. Avoid using such interconnection methods,
unless the exposed metal parts are located within a restricted access location
and users and service people who are authorized within the restricted access
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
The10/100 ports on the Catalyst 3750-24PS and 3750-48PS switches and the
10/100/1000 ports on the Catalyst 3750G-24PS and 3750G-48PS switches
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 of the Catalyst 3750G-24PS switch 10/100 ports or the
Catalyst 3750G-24PS switch 10/100/1000 ports can deliver up to 15.4 W of PoE.
On the Catalyst 3750-48PS or 3750G-48PS switches, any 24 of the 48 10/100 or
10/100/1000 ports can deliver 15.4 W of PoE, 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 Catalyst 3750 PoE port
automatically provides power when an IP phone or an access point is connected.
The device manager and the CLI provide two PoE settings for each 10/100 or
10/100/1000 PoE port: Auto and Never.
When you select the Auto setting, the port provides power only if a valid powered
device, such as an IEEE 802.3af-compliant powered device, a Cisco pre-standard
IP phone, or a Cisco pre-standard Cisco access point, is connected to it. The Auto
setting is the default. However, when you select the Never setting, the port does
not provide power even if a Cisco IP phone or an access point is connected to it.
For information about configuring and monitoring PoE ports, see the device
manager online help and the switch software configuration guide.
Cisco enhanced power negotiation allows some powered devices, such as the
Cisco 7970G IP Phone, to operate in high-power mode on Catalyst 3750 PoE
switches. The powered device and the switch negotiate through power-negotiation
Cisco Discovery Protocol (CDP) messages for an agreed-upon
power-consumption level. The negotiation allows a high-power Cisco powered
device that consumes more than 7 W to operate at its highest power mode. The