Netgear S3300-28X-PoE+ (GS728TXP) - ProSAFE S3300 Smart Switch Series ハードウェアマニュアル

If the suggestions in the troubleshooting chart do not resolve the problem, see the following 
troubleshooting suggestions:

Network Adapter Cards. Ensure that the network adapter cards installed in the 
computers are in working condition and the software driver was installed.

Configuration. If problems occur after you alter the network configuration, restore the 
original connections and determine the problem by implementing the new changes, one 
step at a time. Ensure that cable distances, repeater limits, and other physical aspects of 
the installation do not exceed the Ethernet limitations.

Switch Integrity. If necessary, verify the integrity of the smart switch by resetting it. To 
reset the smart switch, disconnect the AC power from the smart switch and then 
reconnect the AC power. If the problem continues, contact NETGEAR technical support:

Phone (US & Canada only): 1-888-NETGEAR.

Phone (other countries): Check the list of phone numbers at 

Autonegotiation. The RJ-45 ports negotiate the correct duplex mode, speed, and flow 

control if the device at the other end of the link supports autonegotiation. If the device 
does not support autonegotiation, the smart switch determines only the speed correctly, 
and the duplex mode defaults to half-duplex.

The Gigabit Ethernet ports negotiate speed, duplex mode, and flow control if the attached 
device supports autonegotiation.