AT&T 410 820 - Manual (Page 8)

CONFERENCE
Add a second outside caller to an existing conversation by
following this procedure: Touch Conference, touch a free line
button, dial the second person.
Conference
+ 555-1234 +
You can also use the Conference feature to add in a call on
hold: Touch Conference, touch the line button with the held
call.
Conference
+
555-1234
The conference limit is two outside lines. Two additional inside
people can join in the call by touching the line buttons in use
for the conference, making a total of five people in the con-
ference, including you.
If you put a conference on hold, the other people in the con-
ference can talk to each other. This is especially convenient if
two outside parties need to talk to each other. You can con-
ference them together, put them on hold, and be free to do other
things.
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