AT&T MERLIN LEGEND Reference page 54

Features
Feature Interactions
Auto Dial
The feature code assigned to Automatic Callback by the local telephone
company can be programmed on an Outside Auto Dial button.
Directory
The feature code assigned to Automatic Callback by the local telephone
company can be programmed as an entry in the Personal or System
Directory on an MLX-20L telephone.
Speed Dial
The feature code assigned to Automatic Callback by the local telephone
company can be programmed as a System or Personal Speed Dial code.
Automatic Callback
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