AT&T MERLIN LEGEND System Reference Manual page 248

Features
Single-Line Telephones
Considerations
Headset Hang Up
Headset Hang Up cannot be programmed on a QCC. The QCC system operator
with a headset uses the Release or Forced Release button to disconnect calls.
Before Headset Hang Up can be used, headset operation must be activated
either automatically following centralized programming of a Headset Hang Up
button or manually by using a Headset Status button. Once headset operation is
active, the MLX telephone user or system operator (excluding the QCC system
operator) disconnects a call manually by pressing the programmed Headset
Hang Up button. The user cannot use feature codes to activate the feature.
Headset Status
To manually activate or deactivate the headset operation of the telephone or
console, the MLX telephone user presses the Headset Status button. The green
LED next to the button is on when the feature is active and off when the feature
is not active. The user cannot use feature codes to activate or deactivate the
feature. MLX display telephone users can select the feature from the display
only during programming.
Note: A Headset Hang Up button cannot be assigned to a QCC. Therefore, the
Headset Status button is the only way the QCC system operator can activate
and deactivate headset operation.
The Headset options cannot be used on single-line telephones.
Headset operation is automatically activated when a Headset Hang Up
button is programmed and automatically deactivated when a Headset Hang
Up button is removed. This occurs even if the user manually activated or
deactivated headset operation before the Hang Up button was assigned via
centralized telephone programming.
If a telephone or console (for example a QCC) does not have a Headset
Hang Up button, the Headset Status button is the only way headset
operation can be activated and deactivated.
Headset Auto Answer and Headset Hang Up do not work unless headset
operation is activated either automatically following centralized programming
of a Headset Hang Up button or manually by using a Headset Status button.
A headset, handset and speakerphone cannot be used at the same time.
The user should deactivate headset operation before the Headset Hang Up
button or Headset Status is removed. If headset operation is active, the user
exits telephone programming prematurely.
Headset Status button is also programmed by the telephone user or system
operator (excluding QCCs).
Headset Status is a fixed feature on a QCC.
Headset Options 2-199