AASTRA 4225 for MX-ONE Telephony Switch - Manual (Page 14)

Description
Dialog 4223 Professional/Dialog 4225 Vision 14
Tones and signals
The following different tones and signals 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.
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