Asterisk as Auto Attendant/Voicemail to Legacy PBX System

I was just wondering whether Asterisk can be configured as a Auto Attendant to existing legacy pbx systems using the digium FXO cards functioning as extensions to the PBX.

I’m mostly concerned with how to do a monitored or supervised transfer to other extensions.

Is this possible with Asterisk?? If yes, I appreciate if someone could at least show how…Thanks.

90% of the time the answer is yes… but it really depends on your current PBX.