AASTRA DT4x2 for MX-ONE User Guide EN - Manual (Page 28)

Description
DT412/DT422/DT432 28
Tones
The following different tones are sent from the exchange to your
phone.
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.
Ring signals
You can change the ring signals, see section “ Ring signals ” on
page 114.
Dial tone
Special dial tone
Ringing tone or queue tone
Busy tone
Congestion tone
Number unobtainable tone
Call waiting tone
Intrusion tone
Conference tone every 15 seconds (to all parties)
Verification tone
Warning tone, expensive route