AT&T MERLIN LEGEND Analog Direct-Line Console Operator's Manual page 25

Understanding Your Equipment
ICOM or SA buttons are labeled Ring, Voice, or Orig
(Originate) Only. Ring means that co-workers will hear their
phones ringing when you call. Voice means that co-workers
will hear your voice over the speakerphone. Orig Only means
that you can only make calls with this button. (You may not
have this button on your console.)
Line buttons can also be labeled with co-workers' names and
extensions and programmed as inside Auto Dial buttons to
provide one-touch dialing of co-workers' extensions.
Operator feature buttons used for operator-specific features
your company might select are also programmed onto line
buttons. These features are Night Service, Send/Remove
Message, and Alarm. You can program any remaining
unlabeled buttons with additional features. See Chapter 4,
"Using Features".
The following illustration shows an example of programmed
and labeled line buttons.
1-12 Line and DSS Buttons