AT&T MDW 9000 Installation Manual page 58

Set administration and button feature assignment may be done only
by the system administrator. It is recommended that you do not use
features that require visuals (the LCD feature indicator) to be up-
dated while the set is turned off. Also, since some features, such as
Send All Calls, provide visual indication that the feature is turned on,
be aware that if you turn off the handset when using that feature, you
may forget that the feature is on.
System 75 and DEFINITY G1 and G3 system buttons should be
assigned as follows; 1, 2, 3, 4, and 5 are line or feature buttons:
System 85 and DEFINITY G2 system buttons should be assigned as
follows: 3, 4, 5, 6, and 7 are line or feature buttons:
54
PMUTE
18
MSG
ON
RANGE
PMUTE
18
MSG
ON
RANGE
BATT
BATT