Sony SPP-M502 - Manual (Page 30)

Receiving a call while talking
If another call comes in while talking, the LINE 1 or LINE 2 button on
which another call is coming will flash.
1
Press
(
HOLD).
The line in use is put on hold.
2
Press (LINE 1) or (LINE 2), on which another call is coming.
3
Press (CONF) (conference).
Now you can talk to both parties. (Three-way conference)
Tip
If you do not press (HOLD ) in step 1, line 1 will be disconnected.
Having a conference call (continued)
To disconnect the lines during a three-way conference
To disconnect both lines at the same time, press (OFF).
To disconnect line 1 and talk on line 2 only;
Press (LINE 2).
To disconnect line 2 and talk on line 1 only;
Press ( LINE 1 ).
To put the lines on hold during a three-way conference
Press (HOLD). Both lines are put on hold.
To resume the conversations on both lines;
Press (CONF).
To resume the conversation only on one line;
Press ( LINE 1) or ( LINE 2). for the line you want. (The other line is kept
on hold.)
Tip
During a Ihree-way conference, you cannot use “call waiting" service even if
you press ( FLASH ).
30^" Advanced Features