AT&T System 25 - Manual (Page 56)

Exclusion
❑
This feature prevents others from listening in on a shared line.
While on a call, activating this feature will automatically
disconnect all other inside lines. To include selected inside
people on your call, press
EXCLUSION
before adding them to the
call.
Activating Exclusion
1 Answer or place a call.
2 Press
EXCLUSION
.
The light next to this button turns on.
NOTE: The Exclusion feature goes off automatically at the
end of your call.
Display
Activating the Exclusion feature does not affect the current
display.
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