Dolby(R) Noise Reduction

The Dolby(R) Noise Reduction (NR) button, when equipped, is a non-latching momentary contact control that serves a dual function with the radio preset button number 4:
^ Pressing the NR button in the tape mode switches Dolby(R) noise reduction off or on
^ A Dolby(R) symbol appears in the display while this function is active.