AT&T MERLIN LEGEND Analog Direct-Line Console Operator's Manual page 72

Using Features
To Change
Telephones
1. Lift handset.
2. Dial #45 for ES1, or #44 for
3. Hang up.
To Change Extension Status from Multiline
Telephones
1. Press programmed Feature button without lifting the handset.
See Note.
2. Dial 45 for ES1, or 44 for ES2.
Note: Analog multiline phones have a programmed Feature
button and digital/ISDN phones have an imprinted Feature
button.
Extension Status from Single-Line
ES2.
Extension Status 4 - 1 9