zvoniti

1. (of a phone, bell) to ring
   Telefon ti zvoni već pet minuta. — Your phone has been ringing for five minutes.
   Crkvena zvona zvone svake nedelje ujutru. — The church bells ring every Sunday morning.
2. (na vrata) to ring the doorbell
   Neko zvoni na vrata, otvori, molim te. — Someone's ringing the doorbell, please get it.
3. (impersonal, in the ears) to ring in one's ears
   Posle koncerta mi je celu noć zvonilo u ušima. — After the concert my ears were ringing all night.

To phone someone is usually zvati or pozvati, not zvoniti.