HP NC373F PCI-E Multifunction 1000SX Gigabit Server Adapter - Manual (Page 7)

Introduction 7
LED indicators
The NC373F adapter has a single fiber LC port and LED indicator for link activity.
LED indicator Status Description
LNK/ACT Off No link to the adapter is established. The
adapter is not receiving power or the cable
connection is faulty. No link to the adapter is
established.
On Link to the adapter is established. The adapter
is receiving power and the cable connection is
good.
Flashing The adapter is sending or receiving network
data at 1000 Mb/s.