AT&T MERLIN LEGEND System Reference Manual page 300

Features
Single-Line Telephones
Considerations
Once the loudspeaker paging system is accessed, the user dials the assigned
code number for the paging area, if required by the loudspeaker paging
system, and speaks into the handset.
Single-line telephones cannot be used to make voice-announced inside calls
(Speakerphone Paging directed to an individual telephone). To direct
Speakerphone Paging to a group of telephones or to all telephones by using
Page All, the single-line telephone user lifts the handset (while listening to
internal dial tone), dials the extension for the paging group or Page All group,
and speaks into the handset.
To use Loudspeaker Paging, the single-line telephone user lifts the handset
(while listening to internal dial tone), dials #9 (Pickup) and then the paging port's
line number, and speaks into the handset. The paging port is normally not
assigned to a single-line telephone.
A QCC system operator cannot make or receive voice-announced inside
calls (speakerphone paging calls to an individual telephone).
A maximum of seven speakerphone paging groups are allowed; a maximum
of ten telephones are allowed in the first six groups, and the seventh group
contains all telephones and is used for Page All.
When the system includes the large processor module and the Page All
extension is dialed (factory-set at 799), a delay occurs after the first digit is
dialed. This is normal operation and the call goes through.
A QCC cannot be a member of a speakerphone paging group and cannot
receive group pages. However, it can make announcements to a paging
group.
A telephone can be assigned to more than one speakerphone paging group.
A telephone without a speakerphone, loudspeaker, or speakerphone adjunct
cannot be a member of a speakerphone paging group.
When a user tries to direct an announcement to a speakerphone paging
group that is receiving a page, the user hears a busy signal.
When a group member does not hear the announcement, the caller is not
notified unless all telephones in the group cannot hear the page, in which
case, the caller hears the busy signal.
If an analog multiline telephone user does not have Voice Announce to Busy
and the user lifts the handset while listening to a speakerphone page, the
user is disconnected from the page.
If a user on an analog multiline telephone with Voice Announce to Busy or a
user on an MLX telephone lifts the handset while listening to a page, the
page continues and the user can still make a call.
A maximum of three line jacks can be programmed as loudspeaker paging
ports and used to connect a single-zone or multi-zone paging system. Each
of these requires its own loudspeaker paging jack, and users cannot use
more than one paging system at a time by dialing a single access code.
Paging 2-251