Acer E110 - Manual (Page 27)

27 Onscreen call options
Conference calls
If you have one or more calls on hold and another online, you
can combine all calls to create a conference call.
After the first call is established, press the Menu button to
bring up the dialog box. Tap Add call to add the second call.
Tap Merge calls to start the conference call.
To end the conference call, tap End call.