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DT290
Audible Signals
Audible 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
every 4 seconds
Busy signal
Congestion tone
Number unobtainable tone
Call waiting tone
Intrusion tone
Conference tone
every 15 seconds (to all parties)
Verification tone
Warning tone, expensive route