Samsung SCX-5639FR-XAA - Manual (Page 124)

Understanding the status LED
124 4. Troubleshooting
Wireless
LED Blue On When the machine is connected to a wireless network, Wireless LED lights on blue.
a. Estimated cartridge life means the expected or estimated toner cartridge life, which indicates the average capacity of print-outs and is designed pursuant to ISO/
IEC 19752. The number of pages may be affected by operating environment, printing interval, graphics, media and media size. Some amount of toner may remain
in the cartridge even when red LED is on and the printer stops printing.
Status Description