Brother MFC-9450CDN - Manual (Page 24)

Chapter 1
8
Data LED indications
1
The Data LED (light emitting diode) will flash and turn on or off depending on the machine’s status.
LED LED Status Machine Status Description
LED is off. Ready Mode The power switch is off or there is
no print data in the machine.
LED is on. Data Remaining in Memory Print data remains in the machine
memory.
LED is blinking. Receiving Data The machine is either receiving
data from the computer,
processing data in memory, or
print data.