AT&T MERLIN LEGEND System Reference Manual page 183

Features
Paging
Park
Pickup
Saved Number Dial
Signaling
System Numbering
2-134 Direct Station Selector
Pressing a DSS button for a line/trunk programmed as a loudspeaker paging
port only indicates whether or not the paging system is in use. The button
cannot be used to gain access to the loudspeaker paging system. It can be
used only to dial an extension for a paging group.
When a DSS button for a paging group is pressed, the transfer process is not
automatically initiated even if One-Touch Transfer (DLC only) or automatic
Extended Call Completion (QCC only) is programmed for the system.
Park zone codes cannot be assigned to the DSS buttons on a MERLIN II System
Display Console. For the park zones to be assigned to a DSS connected to an
MLX system operator console, the extension numbers must be in the range
programmed for the Page buttons.
When a system operator parks a call by using an associated DSS button and
the call returns, the red LED associated with the park zone where the call was
parked goes off and does not flash, as it does for a transfer return.
To park a call at a park zone, the system operator with a DSS presses the DSS
button for the park zone while the caller is on the line. If a system operator tries
to park a call by pressing the Transfer button followed by the DSS button for the
park zone, the call is put on hold for transfer and is not parked. This can transfer
a call to an outside number in error.
The DSS buttons associated with a line/trunk number (801-880) cannot be used
for answering calls on specific lines/trunks via the Individual Pickup feature.
These DSS buttons are used strictly for busy or not busy status of each
line/trunk.
An extension dialed by pressing a DSS button is not stored for Saved Number
Dial.
If a user presses a Manual signal button programmed with the system
operator's extension while making a call to the system operator, the LED next to
the user's DSS button changes from flashing to on while the Manual signal
button is held down.
The beginning extension for the range of 50 or 100 extensions represented by
each Page button is assigned by using the System Renumber option from the
System Programming menu. The factory setting is that Page 1 begins with
extension 0, Page 2 begins with extension 50, and Page 3 begins with extension
100.