Distinctive ringing is a feature that allows you to set different ringing tones for different numbers in your contact list. This way, you can know from far who is calling, without actually having to watch for a number or name.
Moreover, if your primary line has more than one number, say one for your home and one for your business, you can assign different ringing tones to each of them so that you can know whether you should answer as a manager or as an individual.

