Line out
The number of line outputs (see above) provided in the design of the radio. It should be noted that usually these outputs use RCA connectors (“tulip”), and the analog format allows only one audio channel to be transmitted through one such. Therefore, to work with a stereo signal,
two RCA connectors are required, and just a pair of such jacks is considered to be one line output - a set designed for one set of stereo speakers. The main difference between this interface and the same RCA used to connect speakers (see above) is that the line output receives a signal from a preamplifier that is unsuitable for feeding to passive acoustics. Such a signal must be sent to active speakers or an external amplifier (whereas the speaker is connected to the output of a power amplifier designed for passive speakers).
Fast charge
The function of accelerated charging of external devices - for example, smartphones - from the USB port of the radio. The general principle of this procedure is that increased power is supplied to the gadget; but its specific features may be different. For example, some models provide a separate USB port intended only for fast charging, while others use the same connector to which flash drives are connected. In addition, the radio may support special
fast charging technologies; they speed up the process even more, but only work with compatible devices; for other gadgets, accelerated charging may not be available at all. It doesn’t hurt to clarify all these nuances before purchasing.
Illumination colour selection
The ability
to choose the backlight colour for the control panel, and sometimes also for the radio display. The specific range of shades available can vary, whether it be a few colours or the entire
RGB palette; see "Illumination colour" for details. Anyway, this feature does not play a functional role, however, it allows you to customize the appearance of the device so that it is in harmony with the appearance of the dashboard and matches the user's mood.
Backlight
The colour of the backlight plays primarily an aesthetic role, allowing you to choose a radio for the design of the dashboard and user preferences. In addition, some colours have a practical meaning. So, the
red backlight is extremely popular nowadays also because it is almost perfect for the dark time of the day: this shade does not knock down "night vision" and has a stimulating effect on the nervous system. And
green, on the contrary, relieves excessive nervousness and promotes peace of mind. Other popular colours in modern times include
white,
blue,
orange,
yellow,
purple ; they do not have such pronounced effects, here the main selection criterion is “like or dislike”.
Also note that in many models several backlight colours are indicated at once. This means that the device has a backlight with adjustable colour selection. At the same time, there are models with a choice of a full range of RGB colours.
