| Merlin legend
On MLX telephones, there is a circuit board that can be installed in the bottom of the phone. This board can give you a single line phone, or an alert device, with its own extension number independant of the MLX phone. This board is called an "adjunct"
On TDL phones, which "replace" the MLX phones, there is no physical adjunct boad available, but the adjunct extensions still exsist in the memory of the switch.
Since hardly anyone really uses the adjunct boards, the adjunct extension numbers can become "phantom" extensions for things like pointing DID numbers at, or guest mailboxes, or departmental extension numbers that are then covered to groups of extensions, etc. |