AT&T MERLIN LEGEND Release 3.0 Programming Summary Manual page 54

Select System Numbering Plan
You select only one of the numbering plans (2-digit numbering, 3-digit
numbering, or Set Up Space numbering). In addition, you may need to
perform single and/or block renumbering. You do not need to assign DSS
Page buttons unless the system programming console or one of the operator
positions is connected to a DSS. No matter which procedures you need to
perform, assign the numbering plan first, then do single and/or block
renumbering, and finally, assign DSS Page
Use the single renumbering procedure any
are changing from or to are not sequential.
Block renumbering is quicker, but you can use block renumbering only when
the extension numbers you are changing from and to are sequential.
When trunk or extension modules are removed from the control unit, the
remaining modules must be rearranged so that no empty slots remain. The
system does not acknowledge any modules installed after an empty slot;
therefore, if the system is renumbered, extensions are not assigned to
extension jacks after the empty slots.
3-2 System Renumbering
buttons (if necessary).
time the extension numbers you