AT&T MERLIN LEGEND Analog Direct-Line Console Operator's Manual page 31

Understanding Your Equipment
DSS Button Lights
Each DSS button has a green light next to it. This light
provides the following information. The Message Status light
must be off when you check this information.
Light
Off
Steady
Fast flashing
Slow flashing
1 - 1 8 L i g h t s
Meaning
This co-worker is not on the phone and is
not using Do Not Disturb. (For more
information about Do Not Disturb, see the
Analog Multiline Telephones User's
Guide.)
This co-worker is on the phone or is
using Do Not Disturb. (For more
information about Do Not Disturb, see the
Analog Multiline Telephones User's
Guide.)
This co-worker is calling you.
A call you transferred to this extension is
returning to you.