International call progress tones for IP-PBX and VoIP telephony
Telephone Line Signalling
Positive indication tone
Also known as the Acceptance tone, Function acknowledge tone, Positive indication tone and the Service activated tone.
A tone used to indicate that an exchange has received information from an access line or has processed a request received from an access line, such as the activation/deactivation of line services.
It may also indicate that an interrogated service is active.