Acer ALH-616ds User Manual page 19

Note: It's normal either Master or Slave LED will display when hubs
are stacking.
Note: The difference between Master hub and Slave hub will be
Collision: Indicate if a collision occurs in 10Mbps or 100Mbps domain.
10 Collision Orange Blink
100 Collision Orange Blink
Bridge: Indicates if the bridging function is enabled.
Color
Green
Note: The slave hub will provide a Bridge Uplink Port, see chapter 3 for
2.4.3 Network Status Indicators
There are 3 LED indicators to indicate the network status of each connection
port.
Color
Master Green
Slave Green
explained in chapter 3.
Color
On/Off
On
Off
details
On/Off
On
Off
On
Off
On/Off Indication
Collision in 10Mbps domain
Off Normal
Collision in 100Mbps domain
Off Normal
Indication
Bridge function enabled
Bridge function disabled
Indication
Master
Malfunction
Disable
Malfunction