— an interface for transmitting line-level analogue audio. In monitors, this term can mean both line-out and line-out (or even both options at once). The specific equipment option should be specified in each case separately. Here we note that the line input is intended for receiving an audio signal from computer sound card (or other similar source) and further outputting sound to the built-in speakers or to an audio output of one format or another. The line output, in turn, is mainly used to connect active acoustics or an external power amplifier. However, in some monitors, this output can also play the role of headphone jack.
