I've configured the DVX-2005F to allow communication between IP phones (DPH-400SE) and I managed to have FXO line to dial-in the phones, however, I can not manage to let IP Phone pickup FXO line (multiplexing). I have tried it several times and very confused about DISA, DID, DOD and these expressions.
Simply, I need to pick up the phone, dial an extension (which I can't manage to assign) to call the FXO (PSTN) telephone line. Very simple!