I have a DK16 and Stratagy Flash combo. The DK16 is rev 3 and the Flash is R3. When I set CFNA code "603" and have calls go to voice mail after 16 seconds, station to station calls that are voice first after 16 seconds are simultaneously connected to the station and can hear the personal greeting of the called station. Example: x10 intercoms x12, x12 can talk to x10 after 16 seconds elapses x10 hears both the person talking on x12 and the mailbox greeting.