AT&T MERLIN LEGEND System Reference Manual page 129

Features
Hold
Inspect
Multi-Function Module
Music-on-Hold
Paging
Park
Pickup
Queued Call Console
2-80 Conference
The conference originator receives the Hold Reminder tone when the
conference is on hold for more than one minute as a result of using the Hold
button or adding other participants. If DLC Operator Automatic Hold is
programmed and used by a DLC system operator setting up a conference, the
entire conference goes on hold.
Both sides of an inside call cannot be put on hold. Therefore, if the user presses
the Hold button while waiting on hold for a conference initiated by another user
(an inside call), or if the user presses the Conference button while waiting on
hold on an inside call, all participants are disconnected.
If the user presses the Conference button while Inspect is activated, Inspect is
canceled and the system tries to activate the Conference feature.
When a user joins a conference by using a shared outside line or Shared
System Access button, the queued call console (QCC) display reflects the
correct number of participants. However, if the QCC system operator uses the
Inspect feature to verify the number of participants, the number shown on the
display does not include participants joining the conference on a shared button.
The Conference feature cannot be used on the MFM since the system ignores
the switchhook flash sent by the MFM.
If the first participant put on hold for a conference is an outside call, the caller
hears Music-on-Hold until the second participant is added.
Speakerphone and loudspeaker paging calls cannot be added to a conference.
Conference calls can be parked by all users except a QCC system operator.
They remain parked and do not return to the originating telephone if the Call
Park Interval is exceeded. If a QCC system operator tries to park a conference
by pressing the Start button and then pressing the DSS button for the Park zone,
the park is denied and the system operator is reconnected to the conference.
A conference call cannot be picked up at another telephone. A conference
originator can, however, pick up a call and add it to the conference.
When a QCC system operator arranges a conference call, the result is that all
conference participants (a maximum of five) are connected together on one Call
button. This allows the system operator to put the conference on hold and still
have other Call buttons to make and receive calls. However, since all
participants are on one Call button, the system operator can drop only the last
participant added to the conference.