Cisco Systems SG300-28SFP Plumbing Product User Manual


 
Cisco 300 Series Managed Switches 7
NOTE The switch can deliver a maximum of 15.4 Watts to any 10/100 or
Gigabit PoE port. The 24MP, 28MP, 52P and 52MP models of the switch
can deliver a maximum of 30 Watts to any PoE port.
WARNING The switch is to be connected only to PoE networks without
routing to the outside plant.
CAUTION Consider the following when connecting switches capable of
supplying PoE:
The PoE models of the switches are PSE (Power Sourcing
Equipment) that are capable of supplying DC power to
attaching PD (Powered Devices). These devices include VoIP
phones, IP cameras, and wireless access points. The PoE
switches can detect and supply power to pre-standard
legacy PoE Powered Devices. Due to the support of legacy
PoE, it is possible that a PoE switch acting as a PSE may
mistakenly detect and supply power to an attaching PSE,
including other PoE switches, as a legacy PD.
Even though PoE switches are PSE, and as such should be
powered by AC, they could be powered up as a legacy PD
by another PSE due to false detection. When this happens,
the PoE switch may not operate properly and may not be
able to properly supply power to its attaching PDs.
To prevent false detection, you should disable PoE on the
ports on the PoE switches that are used to connect to PSEs.
You should also first power up a PSE device before
connecting it to a PoE switch. When a device is being falsely
detected as a PD, you should disconnect the device from the
PoE port and power recycle the device with AC power
before reconnecting its PoE ports.