AT&T SYSTEM 25 User Manual page 8

Handset Tones
System 25 signals you with tones that you hear through the
DIAL TONE
You can dial.
CONFIRMATION TONE
Your action has been accepted.
RINGBACK TONE
tone)
The number you dialed is ringing
SPECIAL RINGBACK TONE
one short, dull tone)
The person you dialed has Call Waiting.
BUSY TONE
The number you dialed is busy.
FAST BUSY TONE
The number or access code you dialed is busy, restricted, or
misdialed.
CALL WAITING TONE (one or two tones heard during a call)
(one short tone: the waiting call is an inside call)
(two short tones: the waiting call is an outside call)
You have another call-waiting.
QUEUING TONE
Your callback request for a busy station or outside line has been
confirmed.
DEQUEUING TONE
The station or outside line that you requested is available, and
your call can now be completed.
(a continuous steady
(three short tones)
Proceed to the next step
(one long tone and
(repeating or/off tone)
(repeating on/off tone)
(five short tones)
(three short tones)
tone)
(repeating on/off
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