AASTRA DT292 for BusinessPhone User Guide EN - Manual (Page 94)

Audible Signals
BusinessPhone – Cordless phone DT292 94
Audible Signals
The following different tones are sent from the exchange to your
telephone.
Tone characteristics
The tones shown in this section are the most used tones
worldwide. Many markets use a differing tone for one or more
situations.
Dial tone
Special dial tone
Ringing tone or Queue tone every 4th second
Busy tone
Congestion tone
Number unobtainable tone
Call waiting tone
Intrusion tone
Conference tone every 15th second (to all parties)
Verification tone
Warning tone, expensive route