Press to turn the printer on or off.
Press to resume printing once an error has been resolved. The printer will then initialize ready for printing.
Also, to cancel printing in progress, press this button.
Off: the printer is turned off.
Green: the printer is ready to print.
Flashing green: the printer is preparing to print, or is currently printing.
Flashing orange: an error has occurred and the printer is not ready to print.
Flashing orange and green alternately: an error has occurred that may require a service call.