4.3 Identifying Tones
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User Manual
While Off-hook
Ringback Tones
Single (3-s interval)
Double (3-s interval)
Single (5-s interval)
Double (5-s interval)
DND Tone
The dialled extension is
refusing incoming calls.
Indication Tones
Tone 1 (Call Waiting Tone)
Tone 2 (Call Waiting Tone)
Single
Double
Triple
Tone 3 (Hold Alarm Tone)
A call has been on hold for
longer than the specified time.
1 s
1 s
1 s
1 s
1 s
15 s
1 s
1 s
1 s
15 s