AT&T MERLIN LEGEND Release 4.0 Feature Reference page 284

Feature Reference
Feature Interactions
Authorization Code
Auto Dial
Automatic Line
Selection
Barge-In
Callback
Caller ID
Conference
Direct Voice Mail
Do Not Disturb
Hold
Paging
Park
284
Headset Options
If a call is made using an authorization code, pressing the Headset
Hang Up button causes deactivation of the Authorization Code feature.
If headset operation is turned on at the telephone or console, select a
line button before dialing an extension or an outside number using Auto
Dial.
Automatic Line Selection does not work when an MLX telephone or
console is in headset operation. A headset user must select a line
manually before making a call.
If Barge-In is used to contact a user with Headset Auto Answer turned
on, the call is answered automatically.
Callback calls are answered automatically when Headset Auto Answer
is turned on, but the user hears the dequeuing tone instead of zip tone.
When both caller and receiver have headsets with Headset Auto
Answer on, the person being called hears zip tone when the callback
call is completed, but the callback originator does not hear zip tone or
dequeuing tone.
When using Headset Auto Answer on an extension, the intercom and
line buttons should be programmed for Delay Ring so that the Caller ID
information, available to the user after the first ring, is not lost.
Headset Auto Answer is turned off automatically while the user sets up
a conference, and must be turned on manually to resume using the
feature.
When an MLX telephone user (except for a QCC operator) transfers a
call using Direct Voice Mail, Headset Auto Answer is turned off and
must be turned on manually to resume using the feature.
If an MLX telephone user with Headset Auto Answer turned on uses Do
Not Disturb, any calls that override Do Not Disturb (such as Barge-In
calls and callback calls) are answered automatically.
Headset Auto Answer is turned off automatically when a user or
operator puts a call on hold and must be turned on manually to resume
using the feature.
A user or operator with a headset operation active hears a group page
over the speakerphone.
If a user or operator has a call parked, another call can be answered
automatically by using Headset Auto Answer.