3Com Baseline 2928 PWR Plus User Manual page 140

Item
Set the port to transmit data at the lowest speed.
Lowest Speed
If you configure the lowest speed limit on a port that does not support 10
Mbps, the configuration cannot take effect.
Shut down the port.
Shutdown
An energy saving policy can have all the three energy saving schemes
configured, of which the shutdown scheme takes the highest priority.
Description
1-2