Modern caller ID, perhaps

• Notes to pick up on?
• Cellphone customer's creation, perhaps
• Sound made by a mobile phone
• One's heard on the phone offering to negotiate, to some extent
• Caller ID, maybe
• Annoying thing to hear in a movie theater
• Bars for a cell?

Wikipedia Word definitions in Wikipedia
A ringtone or ring tone is the sound made by a telephone to indicate an incoming call or text message . Not literally a tone nor an actual (bell-like) ring any more, the term is most often used today to refer to customizable sounds used on mobile phones ...

Wiktionary Word definitions in Wiktionary
alt. the sound made by a telephone when ringing, especially the customizable tone of a mobile phone n. the sound made by a telephone when ringing, especially the customizable tone of a mobile phone