AT&T 75 Telephone User Manual


 
CHAPTER 2. DESCRIPTION
A 3-digit extension number has a 1-digit group select number and a 2-digit DXS
number. For example, the extension number 321 has a 3 group select number and a
21 DXS number.
A 4-digit extension number has a 2-digit group select number and a 2-digit DXS
number. For example, the extension number 4321 has a 43 group select number and
a 21 DXS number.
A 5-digit extension number has a 3-digit group select number and a 2-digit DXS
number. For example, the extension number 54321 has a 543 group select number
and a 21 DXS number.
Determining Extension Number Status
The attendant determines the idle or active status of extension 4321 or 321 by pressing
Group Select button 43 or 3 and looking at the lamp to the left of DXS button 21. If the lamp
is dark, the extension is idle. A call can be extended or originated to that number.
If the lamp is lighted, the call can still be extended. The extension number may be active, but
another answering group member may be available or another call appearance may be idle
on a multi-appearance voice terminal.
Also, the Attendant Call Waiting feature can be
activated for a single-line voice terminal. (Attendant Call Waiting is described in Chapter 4.)
When the number represented by the DXS button is assigned to a group, such as a
terminating extension group or trunk group, the lamp lights only when all members of the
group are busy and the queue, if provided, is full.
If all available call appearances on a multi-appearance voice terminal are active or if the
Attendant Call Waiting feature cannot be activated, the attendant hears busy tone.
Attendant Console Tones
Tones Heard Through Handset or Headset
While operating the console, the following tones may be heard through the handset or
headset:
Ringback Tone
Busy
A low-pitched tone repeated 15 times a minute; the electronic version of the
conventional ringing heard when the number dialed is being rung.
Tone
A low-pitched tone repeated 60 times a minute; indicates that the extension
number dialed is active (busy).
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