Dell P1500 Personal Mono Laser Printer - Manual (Page 65)

What this light sequence means:
The printer is processing data, but the memory used to store pages is full.
What you can do:
Press and release Continue to clear the message and continue
printing the job (the job may not print correctly).
Press and release Cancel to cancel the print job.
Press and hold Cancel to reset the printer.
To avoid this error in the future:
Simplify the print job. Reduce the complexity of the page by
reducing the amount of text or graphics on the page and deleting
unnecessary downloaded fonts or macros.
Install additional printer memory (refer to the Owner's Manual
for instructions).
Secondary error code
What this light sequence means:
The page may not print correctly because the print information on the page
is too complex.
What you can do:
Press and release Continue to clear the message and continue
processing the print job (some of the print data may be lost).
To avoid this error in the future:
Reduce the complexity of the page by reducing the amount of
text or graphics on the page and deleting unnecessary
downloaded fonts or macros.
Set Page Protect to On in the Local Printer Setup Utility.
Install additional printer memory (refer to the Owner's Manual
for instructions).