AT&T MERLIN LEGEND Release 4.0 Feature Reference page 283

Feature Reference
Headset options cannot be used on analog multiline telephones or on
single-line telephones.
A headset user must manually select a line button or Call button (on the QCC)
before making an inside or outside call.
A user can press the Speaker button to move the call from the headset to the
speakerphone.
Privacy should be programmed when headset users with Headset Auto Answer
turned on have Shared SA buttons or share one or more personal lines. Privacy
keeps people from competing for the same call. When two or more users
answer the same call on a Shared SA or personal line button, the red and green
LEDs next to the button go on, but only one person can talk with the caller.
Headset users should press the Headset Hangup button after each call. If the
user does not press the Headset Hangup button, new calls still arrive correctly,
but the LED status of the extension (as shown on other extensions and DSSs) is
not updated.
Telephone Differences
Queued Call Consoles
A QCC does not have a Headset Hang Up button, nor can the button be
programmed. Headset operation is automatically available, and Headset Auto
Answer, Headset/Handset Mute, and Headset Status are fixed buttons on a
QCC.
The function of disconnecting calls served by the Headset Hang Up feature is
replaced by the Release, Forced Release, Camp-On, and Automatic Release
features.
Other Multiline Telephones
Headset options apply to MLX telephones and consoles only.
The telephone user or operator cannot use feature codes or extension
programming to activate Headset Hang Up. This feature must be programmed
on a button through centralized telephone programming.
The telephone user or operator cannot use feature codes to turn Headset Auto
Answer, Headset/Handset Mute, or Headset Status on or off. These features
must be programmed on buttons through extension programming or centralized
telephone programming. MLX display telephone users can select the feature
from the display only during extension programming.
283
Headset Options