AT&T 7406BIS manual Call appearances

Starting at the upper left of Figure 1 and continuing clockwise:

Handset	For placing and answering calls. In most cases, you must lift
	the handset (go off-hook) before you can use a feature. Also
	known as the receiver.
Call appearances/	For handling incoming and outgoing calls (call appearances),
feature buttons	labeled with extension numbers. For accessing features
	(feature buttons), labeled with feature names.
Display	For showing information (2-line, 48-character display).
Select Ring
button	For accessing the Select Ring feature.
Shift button	For accessing the top-labeled features on shiftable buttons.
Display-viewing	For adjusting the viewing angle of the display.
adjustment
Speaker button	For accessing the speaker or the built-in speakerphone and
	microphone combination. Note: Your voice terminal can be
	set for either the Speaker (listen-only) feature or the
	Speakerphone (listen and talk) feature. Check with your
	System Manager to see how your Speaker button is to be
	used.