You probably have Flash at CO set to yes. It must be no for analog port to work correctly.

The sequence for conference is:

Establish your first call.
Press Flash 2 to place call on hold.
Establish your second call.
Press Flash *3 to establish the conference.


Marv CCNA, CTUB
TeleMarv Services (Retired)
Providing telecommunication solutions in Ottawa Canada since 1990