International call progress tones for IP-PBX and VoIP telephony

Telephone Line Signalling

Trunk offering tone

  • Also known as the Busy override warning tone, Busy verification tone and the Trunk offering tone.
  • A tone advising participants during a call that the privacy of the conversation has been breached, e.g. by the intervention of an operator.

Search for Trunk offering tones in the World Tone Database
Back to guide
Related product: CPT-Master tone generator app